Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce

Happy Fourth of July a little early.

These sliders will be perfect for your party. You are having a party, right?

Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce - Meatless comfort food at its finest! Hearty, satisfying and so good!

I have no plans to throw a party, but if I could be invited to one where there’s friends, good food, and the drinks are flowing, and not have to worry about hosting it, I wouldn’t say no.

The sliders are filling, satisfying, meatless, and definitely healthier than a greasy burger or typical cookout fare. Try them for a meatless weeknight dinner if you’re trying to lighten things up.

Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce - Meatless comfort food at its finest! Hearty, satisfying and so good!

For the filling, I caramelized a Vidalia onion in olive oil along with baby portobello mushrooms and pickles. The resulting combo is a meaty (minus the meat) sandwich that’s hearty, chewy, with subtle crunch from the onions and pickles.

I used Bread and Butter Chips from Farmer’s Garden® by Vlasic®. I love pickles but many brands are loaded with a ridiculous amount of sodium which is why I’ve started pickling my own vegetables. Thankfully the Vlasic pickles aren’t salt bombs and I love their sweet-and-tangy zip. They’re artisanal-quality, premium pickles, made with honest ingredients and no artificial flavors. They’re made with deliciously ripe cucumbers, whole garlic cloves, slices of red bell pepper, rounds of carrots, fresh herbs and spices and hand-packed in glass jars.

Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce - Meatless comfort food at its finest! Hearty, satisfying and so good!

Before filling the sliders, I coated the bread with fry sauce. If you’ve never had it, you’ve got to try it. Sometimes fry sauce is called Utah sauce or Utah fry sauce, but I waitressed in a dive bar in Minnesota in college and this is the sauce we served with wings and waffle fries so it’s not just a Utah thing.

It’s two parts ketchup to 1 part mayo (use vegan mayo) with a splash of pickle juice. Now you have a use for pickle juice rather than just tossing it.

The sauce is excellent on fries, but it makes a great sandwich spread and even for mayo-haters, it’s not overly mayo-ey.  I like a little food with my bowl of sauce or dip and can devour a batch on about 7 fries.

Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce - Meatless comfort food at its finest! Hearty, satisfying and so good!

I loved this filling mixture and didn’t even need buns. My family didn’t even realize it was meatless.

Comfort food at its finest.

Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce - Meatless comfort food at its finest! Hearty, satisfying and so good!

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Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce

The sliders are filling, satisfying, and definitely healthier than a greasy burger or typical summer cookout fare. Make them for a meatless weeknight dinner if you're trying to lighten things up. They're vegan (use vegan buns or make your own vegan bread), and you'll never miss the meat because they're hearty and packed with flavor. The filling is a caramelized a Vidalia onion, baby portobello mushrooms, and pickles. The resulting combo is a meaty (minus the meat) sandwich with chewiness and a subtle crunch from the onions and pickles. Fry sauce coats the slider buns (use vegan mayo) and it's excellent on fries and makes a great sandwich spread. Vegan comfort food at its finest.

Yield: 6 generously-filled sliders

Prep Time: 10 minutes

Cook Time: about 20 minutes

Total Time: about 30 minutes

Ingredients:

Sliders
1 medium sweet Vidalia onion or yellow onion, peeled and sliced
2 to 3 tablespoons olive oil, divided
4 ounces sliced baby portobello mushrooms
1 cup diced Vlasic Farmer's Garden Bread and Butter Chip pickles
1 teaspoon pickle juice
6 slider buns (use vegan bread, try this or this)

Fry Sauce
1/2 cup ketchup
1/4 cup mayo (or Miracle Whip, use vegan mayo to keep vegan)
about 3 teaspoons pickle juice, or to taste
pinch onion powder, optional and to taste

Directions:

  1. Sliders - Heat a non-stick skillet over medium-high heat, add the onion, drizzle with about 1 tablespoon oil, and allow onion to caramelize, stirring every couple of minutes, or as needed. It takes about 10 minutes for my onions to caramelize and I cook them covered to save time. Lower the heat if onion is browning too fast.
  2. After onion has caramelized, add the mushrooms, pickles, pickle juice, 1 to 2 tablespoons oil or as necessary, and allow mixture  to cook for about 10 minutes, stirring every couple of minutes, or as needed. I cook covered to save time. After about 10 minutes, or after vegetables have softened and wilted, turn off the heat; set aside. While vegetables are cooking, make the fry sauce.
  3. Fry Sauce - In a medium bowl, combine all ingredients and whisk until smooth.
  4. Generously spread fry sauce on both sides of slider buns.
  5. Fill each bun generously with the onion mixture and serve. Sliders are best warm and fresh although extra filling will keep airtight in the fridge for up to 3 days. Extra fry sauce will keep airtight in the fridge for up to 1 month.

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This post was brought to you by Vlasic. Farmer’s Garden is celebrating the authentic taste of #FarmToJar with the Savor Simplicity Sweepstakes from 5/7/14 – 7/31/14. Enter here for a chance to win a weekend cooking adventure or summer entertaining package, each worth $1,500. One winner will be chosen each month. A $1 off coupon will also be given to all entrants immediately following entry. Follow on Facebook

   

38 Responses to “Caramelized Onion and Portobello Mushroom Sliders with Fry Sauce”

  1. #
    1
    Mir — June 16, 2014 at 10:23 am

    Love these! Such a great vegetarian recipe!
    The sauce looks amazing. Like I could eat it with a spoon!

    Reply

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    2
    Kathi@DeliciouslyYum! — June 16, 2014 at 11:31 am

    This has comfort food written all over it, Averie! I’m loving this savory side of yours :). And how about that beautiful fry sauce?? Can’t believe I’ve never heard of it before. When I was a kid, I loved dipping my fries first in ketchup and then in mayo, but never mixed the two. So I know I would be all over this!!

    Reply

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    bev @ bevcooks.com — June 16, 2014 at 11:50 am

    YES. Oh gosh. yes.

    Reply

  4. #
    4
    Polly @ Tasty Food Project — June 16, 2014 at 12:03 pm

    Yum! I love sliders! That sauce looks incredible!

    Reply

  5. #
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    Maryea {happy healthy mama} — June 16, 2014 at 12:06 pm

    Anything with caramelized onions is a winner in my book. This looks soooo good. Pinning to save for later! :-)

    Reply

  6. #
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    Jackie {The Beeroness} — June 16, 2014 at 12:18 pm

    Mushrooms and caramelized onions sound perfect to me!

    Reply

  7. #
    7
    Tracy | Pale Yellow — June 16, 2014 at 12:21 pm

    Caramelized onions and mushrooms are the best! I can’t wait to whip up a batch!

    Reply

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    Krista @ Joyful Healthy Eats — June 16, 2014 at 12:23 pm

    Girl!!! We are so on the same page! I posted portobello burgers last week and sliders today! Great minds think alike!! These look absolutely amazing Averie and love the addition of the fry sauce.. killer!

    Reply

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    Dorothy @ Crazy for Crust — June 16, 2014 at 1:31 pm

    Those are my favorite pickles – they’re sweet. And caramelized Vidalia onions. And mushrooms. This needs to be my next dinner!

    Reply

  10. #
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    Katrina @ Warm Vanilla Sugar — June 16, 2014 at 3:35 pm

    Your fry sauce sounds soooo scrumptious!! love these!

    Reply

  11. #
    11
    Ashton — June 16, 2014 at 4:30 pm

    I’ve been drooling over these since I saw them on IG earlier!! I think the simplicity of this is genius, and I bet these are completely amazing!!

    Reply

    • Averie Sunshine replied: — June 16th, 2014 at 6:18 pm

      I have way more of a sweet tooth than a savory tooth but was totally enjoying the flavors in this so much!

      Reply

  12. #
    12
    Happy Valley Chow — June 16, 2014 at 4:41 pm

    Caramelized onion makes everything taste just a little bit better…Those look flippin amazing! Great job Averie :)

    Reply

  13. #
    13
    Katie — June 16, 2014 at 4:47 pm

    First of all, anything with mayo is overly mayo-y. :P

    Second, I LOVE grilled portobellos and if we lived closer, you would for sure be invited to a BBQ here. BIG TIME. I haven’t grilled mushrooms in forever because my friend who always comes to my BBQs doesn’t like them. That needs to change though. Next time I’m at the store, I’m getting them, and eating them ALL myself! With lots of BBQ sauce or ketchup/mustard/nooch sauce.

    Lastly, caramelized onions are such a delicacy that are so underrated. I used to make a huge batch on weekends and just eat them with a fork, cold, straight from the fridge. Delicious. You can make them in the slow cooker, too, to make them even easier!

    Reply

    • Averie Sunshine replied: — June 16th, 2014 at 6:16 pm

      I wrote that mayo comment JUST for YOU! And seriously though, you will love this sauce. I know you think you hate mayo but honestly this is a doctored up ketchup lover’s dream (and that describes you!)

      I wish I had a backyard, a grill. I wish I had…well, a midwest summer night’s bbq is the best thing ever. Totally wish I could join you!

      caramelized onions are such a delicacy that are so underrated = Yes so true! The mixture itself with the shrooms, too, so good. You could mix in some brown rice, lentils, beans, chickpeas, whatever and it could be like a casserole/side-ish or even main dish. So many ways to go – or you could just eat the caramelized onions by themselves which I’d be fine with :)

      Reply

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    Paula — June 16, 2014 at 5:36 pm

    Mushrooms and onions are soooo good together. I never would have thought to add bread and butter pickles (love those too) so I am intrigued and just have to try this! I’ve never heard of fry sauce either but have used ketchup and mayo together–and now I know what it’s called when you put a little pickle juice in. I am loving these savory recipes of yours! I also like saucy food so this sounds like something I could use on many things.

    Reply

    • Averie Sunshine replied: — June 16th, 2014 at 6:14 pm

      The tanginess of the pickles with the onions and shrooms, Paula, so good! Make the mixture and even just mix in some brown rice, lentils, beans, chickpeas, whatever! It could be like a casserole/side-ish or even main dish. I think you’d love it!

      And the fry sauce. So simple but so, so, so good. You have to make it. Then you will want to slather it on everything. Saucy food, yes. Never dry anything, ever!

      Reply

      • Paula replied: — June 22nd, 2014 at 9:36 am

        I tried this for lunch today and went with your suggestion to add lentils. Perfect meal!! I really love the bread and butter chips in the mix–what made you think of it? It all just works and the fry sauce ties it together. I could eat this again for dinner.. but I’ll try to save the leftovers so Jon can try it when he gets home tonight. I think the fry sauce would be great with parsnip fries.

        • Averie Sunshine replied: — June 22nd, 2014 at 1:22 pm

          What made me think of it is when Vlasic contacted me and wanted a recipe using their new pickles. So I had to think pickles, what goes with pickles, like how could I elevate pickles rather than just plopping them on a sandwich. So I decided to stir fry them. And with what…hmmm, onions, shrooms, and then from there (kind of after the fact) realized that lentils, chickpeas, brown rice, wild rice, so many things would be really good in that mixture! Glad the lentils worked and I hope Jon gets a taste but I would not blame you AT ALL for that not exactly happening :) I had intended to share much of this mixture with the family but…that didn’t happen. I went at it with a fork straight out of my leftovers container. Whoops :)

  15. #
    15
    Phillip || SouthernFATTY.com — June 16, 2014 at 6:00 pm

    I could eat that fry sauce on evvvvverything. Correction… I do eat that sauce on everything! Looks delicious.

    Reply

    • Averie Sunshine replied: — June 16th, 2014 at 6:12 pm

      Love the name of your blog! And so glad you know Fry Sauce, and sounds like you know it well :) Me too!

      Reply

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    16
    caralyn @ glutenfreehappytummy — June 16, 2014 at 6:45 pm

    that fry sauce tho :D

    Reply

  17. #
    17
    Lindsey @ American Heritage Cooking — June 16, 2014 at 7:14 pm

    These do look like they will make my stomach so much happier than a greasy burger! Pretty excited about vidalia onion season down here in GA!

    Reply

  18. #
    18
    Kelly — June 16, 2014 at 9:28 pm

    Love this meatless burger and that fry sauce. Oh my, I think I would find any excuse to slather that on everything – sounds amazing!

    Reply

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    Samina | The Cupcake Confession — June 16, 2014 at 11:05 pm

    Mmmmmm!!!!! I LOVEEEE the sweet crunch of caramelized onions and the meaty texture of these mushrooms is making me drool! And as if that wasn’t enough, there’s this delish mayo and ketchup in fry sauce! SALIVATING!!!!!

    Reply

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    dc — June 17, 2014 at 3:31 am

    Yum! Love mushrooms and onions! I’ve heard of fry sauce just never made it. Now might be the time! As for the pickle juice I use it to marinade chicken for sandwiches…supposedly that’s what they do at chick-fil a (I’ve never even seen one of those tho’).

    Reply

    • Averie Sunshine replied: — June 17th, 2014 at 4:12 am

      I think any acid like vinegar, lemon juice, pickle juice is great for marinating things – really helps kickstart that process!

      Reply

  21. #
    21
    lisatberry — June 17, 2014 at 5:18 am

    I have never had fry sauce this is a must try…these sliders look so good I love small food for some reason it just tastes better.

    Reply

    • Averie Sunshine replied: — June 17th, 2014 at 1:22 pm

      It totally DOES taste better and the fry sauce is crazy good and I want it on everything. Something so simple but so darn good!

      Reply

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    22
    Valerie — June 17, 2014 at 8:57 am

    Delish! Fry sauce sounds intriguing; I wonder if I could swap mustard for ketchup? (I put Dijon mustard on just about everything!) :D

    Reply

    • Averie Sunshine replied: — June 17th, 2014 at 1:10 pm

      It would definitely give it a different flavor but I really don’t think there’s a wrong way to mix condiments together :)

      Reply

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    23
    Lindsay Ann @ Lindsay Ann Bakes — June 17, 2014 at 9:10 pm

    fry sauce??!!??!! I’ve got to make these little cuties just to try that sauce! Looks amazing! Love a little savory in the mix!

    Reply

    • Averie Sunshine replied: — June 18th, 2014 at 1:53 am

      You will LOVE that stuff! So simple but so good!

      Reply

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    Amy @ Amy's Healthy Baking — June 23, 2014 at 11:25 pm

    Oh Averie, these look incredible! The sweet onions, the crunchy pickles, the gorgeous filling… So why oh why do I have to be allergic to mushrooms??? Not fair! Is there anything I could substitute instead? Because these look way too good to pass by! :) We haven’t had a 4th of July party for as long as I can remember, but the past few years my guy and I have camped out at the local park to watch the fireworks. Despite being a tiny town, they actually choreograph them to music — it’s so fun!

    Reply

    • Averie Sunshine replied: — June 24th, 2014 at 1:06 pm

      You could just omit them or use lentils, sweet potatoes, another vegetable – whatever you’d like!

      Reply

      • Amy @ Amy's Healthy Baking replied: — June 24th, 2014 at 2:32 pm

        Caramelized onions and sweet potatoes — now that sounds like perfection! Hard to beat naturally healthy sweetness, and my waistline doesn’t mind that as much as an extra cookie (or four)! ;)

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    Lori — July 15, 2014 at 9:39 am

    Made this for dinner and it was devoured by all. Even my mushroom hating kid loved it (I don’t lie, I told her what was in it). I was very reluctant to add pickles but followed your directions. Sauce also great. Not so quick, carmelizing onions took a while, but fantastic results. Thank you, Averie!

    Reply

    • Averie Sunshine replied: — July 15th, 2014 at 1:19 pm

      The fact that you got a mushroom hating kid to love this, that’s wonderful. And yes the pickles add a nice touch and so glad you like the sauce, too!

      Reply

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