Blueberry Oatmeal Crumble Bars

I was going to call these blueberry breakfast bars. Or blueberry snack bars.

But anytime you feel like eating juicy blueberries with buttery oat crumbles is the kind of bar they are.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

It’s an easy, one bowl, no mixer recipe that takes just minutes to make. I adapted the recipe from Blueberry Pie Bars by reducing some of the flour and adding oats to the crust and crumble mixture. The oats add such great texture.

The crust and crumble topping are one in the same. Love it when that happens so there’s one less step and one less bowl to wash.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

I eliminated the Greek yogurt, sugar, and egg from the filling and kept the focus on the blueberries.

The bars aren’t overly sweet and the blueberry flavor shines beautifully, which is why they’re great for breakfast, brunch, snacks, or a healthy dessert.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

They’re soft and tender, yet slightly chewy from the oats, and I’m a sucker for anything with a crumble topping.

My daughter said they’re one of the best ‘desserts’ I’ve made in a long time. I made the bars on a Sunday and had breakfast ready to grab-and-go for her for the week. One less thing to worry about on busy weekday mornings. Loved that.

Blueberry Oatmeal Crumble Bars - Fast, easy, no-mixer bars great for breakfast, snacks, or a healthy dessert! BIG crumbles and juicy berries are irresistible!!

Print Recipe

Blueberry Oatmeal Crumble Bars

An easy, one bowl, no-mixer recipe that takes just minutes to make. The crust and crumble topping are one in the same so there’s one less step and one less bowl to wash. The bars aren't overly sweet and the blueberry flavor shines beautifully, making them great for breakfast, brunch, snacks, or a healthy dessert. They're soft and tender, yet slightly chewy from the oats, and I'm a sucker for anything with a crumble topping. I made the bars on a Sunday and had breakfast ready to grab-and-go for the week.

Yield: one 8x8 pan, 8 generous wedges

Prep Time: 10 minutes

Cook Time: about 55 minutes

Total Time: about 90 minutes, for cooling

Ingredients:

Crust and Crumble Topping
1/2 cup (1 stick) unsalted butter, melted
1 cup all-purpose flour
3/4 cup old-fashioned whole-rolled oats (don't use quick cook or instant, they're finer and behave like flour and will make mixture too dry)
1/2 cup granulated sugar
1/4 cup light brown sugar, packed
pinch salt, optional and to taste

Blueberry Layer
12 ounces (2 cups) blueberries (fresh or frozen; I used frozen and didn't thaw)
1/3 cup granulated sugar
2 tablespoons lemon juice
2 teaspoons cornstarch

Directions:

  1. Preheat oven to 350F. Line an 8-inch square pan with aluminum foil and spray with cooking spray; set aside. Lining the pan helps with cleanup and is recommended.
  2. Crust and Crumble Topping - In a large, microwave-safe bowl melt the butter, about 1 minute on high power.
  3. Add the flour, oats, sugars, optional salt, and stir to combine. Mixture will be dry and sandy with some larger, well-formed crumble pieces.
  4. Set 1 heaping cup mixture aside to be sprinkled on later as crumble topping.
  5. Transfer remaining mixture to prepared pan, and using a spatula or your fingers, hard-pack the mixture to create an even, smooth, flat crust; set aside.
  6. Blueberry Layer - In a large mixing bowl (same one used for crust and crumble is okay), add all ingredients and toss to combine. If sugar hasn't dissolved fully that's okay because it liquifies while baking.
  7. Evenly distribute blueberry mixture over the crust.
  8. Evenly sprinkle with the reserved heaping 1 cup crumble topping mixture. Before sprinkling, I squeeze the mixture in my palm to encourage bigger crumble pieces to form.
  9. Bake for about 55 minutes, or until edges are set and center has just set. Crumble topping should appear set and very pale golden. I used frozen berries without thawing and the pan was very cold going into the oven. If using fresh berries, baking time will be reduced, but I'm not sure by how much, I'd guess at least 10-15 minutes, possibly less. Bars may take longer than 55 minutes if blueberries are very juicy. Watch your bars, not the clock, when evaluating doneness. Place pan on a wire rack and allow bars to cool for at least 30 minutes before slicing and serving. If you try to slice bars before they've cooled completely, they'll be extremely messy and could fall apart. Bars will keep airtight at room temperature for up to 1 week, in the fridge for up to 10 days, or in the freezer for up to 6 months.

Adapted from Blueberry Pie Bars

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137 comments

  1. Any suggestions for what to use in place of sugar? Would honey work for the topping? I made these this morning and absolutely LOVED them just looking for a bit of a healthier version. 

    • Just as an fyi, sugar has 16 cals per tsp and honey has 22 cals per tsp. So….I wouldn’t necessarily say honey is any better than sugar but that’s a whole other topic; they’re both still forms of sugar. But I digress :)

      Thanks for trying the recipe and I’m glad it came out great for you as written and honestly no, honey as a topping wouldn’t work b/c it would just make everything all mushy, gummy, gooey, and won’t set up. I would say if you’re really concerned, maybe just cut the pieces a little smaller :)

  2. This was a nice recipe, but it was wayyy too sweet.  It seemed like I was eating just sugar.  I even halved the sugar recipe, but it was still too sweet.  I think for next time, I’ll use even less sugar and more flour and oats so it’ll be a healthier treat.

    • Everyone has different sensitivities toward sugar and perhaps your blueberries were just extra sweet to begin with and it sounds like you’re VERY sugar-sensitive if you halved it and even that seemed too much. (That’s only about 1/2 cup total in an entire dessert, including crust and topping, which is pretty minimal!). Thanks for trying the recipe.

  3. I have been staring at this recipe and the blueberry pie bar recipe for two days now.  I want to combine them because I want to do the crumble but I want the creamy yogurt with my blueberries.  My kiddos are wretched about eating fruit so I need to soften it a bit.  Will it work?  Any suggestions?

  4. Hi Averie ~ Thank you so much for putting such Goodness out there!  I totally think your Blueberry Oatmeal Crumble Bars rock! I actually became incredibly inspired by them and created a lemony treat with your recipe as a base. I sent a shout out to you on my blog and I hope it gets you many returns!   I am kinda new at all of this so I hope I’m doing this right… 
    Here is the page:  http://www.prettysexyweightloss.com/Lemony-Blueberry-Oatmeal-Bars.html

  5. I LOVED these! This recipe is definitely going into my “Favorite Recipes” binder! Thanks for sharing!

    The only change I made was in regards to the lemon juice, I didn’t have any. So I used just a couple drops of water instead and they still turned out great! 

  6. These were so great, a big hit! I made the night before to let them set up, which was good.

  7. I just made these. Oh. My. Gosh. These are delicious!!! I was feeling something a little bit sweeter so I mixed up some icing with confectioners sugar and it was the perfect addition!

  8. i made these a few months back and they were great!  So now I have a cup of blueberries in the freezer and some raspberries I need to use…. Living dangerously (haha) I think I’ll combine them.  Wish me luck! 

  9. I made these twice in two weeks.  Second batch I reduced the white sugar in the crumble by half and didn’t pack the brown sugar.  I lowered the sugar in the blueberry goo by a touch too.  Both versions were fantastic and I LOVE how easy this comes together, no leavening ingredients, just easy peasy and only ONE FREAKING BOWL to wash.  You’re a woman after my own heart.  I brought this to a potluck and sadly I only had a postage stamp sized piece before this was gone. Loved by all. Thank you.

    • Thanks for trying the recipe and I’m glad it came out great for you and that you were able to reduce the sugar a little, too! I love ONE BOWL recipes, too! That is so me, all the way, don’t dirty more than one bowl or break out the mixer unless it’s absolutely warranted :) Glad they were a big hit at the potluck, too!

  10. My husband and I loved these!! I want to make another batch and I was wondering if I could use disquick in place of the flour?

  11. Can I use coconut oil instead of butter?

  12. This look so delicious! I will for sure make it tonight for Oscars! Thanks for sharing! 

  13. Oh my goodness I made these morning and ended up serving them with vanilla ice cream for dessert. So delicious! The best blueberry baked good I’ve ever made or tastes. Thanks for the recipe!

  14. Hi there
    I only have quick oats unfortunately! Is there any way to use quick oats yet adjust the rest of the recipe to make it turn out? Less flour??
    Thx!

  15. Hi, I’m excited to try this recipe! I’m on a chia seed kick and like to try to find ways to add them to recipes to give it a healthy boost and because they have a bland flavor they shouldn’t alter the taste here. I’m still new to using chia seeds so my question is if you have experience with them, or if anyone has suggestions, which step here they should be added? Because they can become gel-like when mixed with liquid, I was thinking of adding them to the crust/crumb topping, but I didn’t know if the melted butter would doing something weird. Thoughts? Haha I know this is such an odd question, but a girl’s got to look for ways to be healthy when eating something that sounds so delectable! Thanks!

    • This wouldn’t be a recipe I’d add chia seeds to. There are too many things that can go wrong from the crust not setting, the crumble turning gooey on account of the chia seeds, the blueberry consistency becoming off from them – I personally wouldn’t add them here.

  16. Looks sooO good! can’t wait to try them!

  17. This is a perfect recipe! I didn’t change any measurements and they came out perfect. I used my gluten free flour blend one for one as you would regular flour. I can’t wait to try with cherries or raspberries. Thank you for a great recipe! This will be on rotation in our house.

  18. I made these using strawberries. My husband loved them, he said they were sweet. I meant to reduce the amount of sugar due to the sweetness of the strawberries, but my mother called just as I started, so I ended up just

    following the recipe.
    My husband started suggesting other fruits to use, bananas, apples, so I will have to do some experimenting. Thanks for a great recipe.

  19. Your blueberry bar recipe is absolutely delicious, i tweaked a few ingredients and OMG it will be one that I repeat over and over.  Thanks,  I will feature it in my blog sugarsaltspice.com  I will give you credit for this.  Love your blog.

  20. Made BLUEBERRY OATMEAL CRUMBLE BARS tonight and I can tell you they won’t last long!  I’m not a fan of white flour so I did use 1/2 white and 1/2 whole wheat.  My husband loved them.  May even try a more whole wheat and less white flour the next time.  Also I used frozen blueberries.  Thank you for sharing :)

  21. The step about cooking spray is no joke. Absolutely use foil and coat the sides of the lined pan like your life depends on it!

    And don’t skimp on the foil. Make sure that bad boy is COVERED. It gets hot and bubbly before it becomes a seriously sticky awesomeness. It took me no less than 20 minutes to cut and remove 4 pans of bars (9 squares each).

    Learn from my mistakes. Use lots of foil and cooking spray.

  22. The recipe is great! I tripled it. I am pleased with the result except that the tin foil baked onto my pan! It only peels off in little shards. I’m not sure what I did wrong, but I think I would try parchment next time or else really grease the pan.

    • Different brands of foil vary in thickness and durability. I use very heavy duty foil. I like foil in this recipe because the juice of the blueberries, with the sugar, and the metal pan…things can get really sticky/stuck and I find foil easier but do what you think will work best. Glad you loved and tripled the recipe!

  23. Thank you for a great recipe!  
    I’m too lazy to wake up early in the morning – to bake something more elaborate for breakfast; and the size of the bake fit my toaster oven – no need to use the big oven – :) 
    Although your blueberry bars were easy and fast to make, they are really good.  I had to change filling – I had 1 cup of fresh blueberries only. I took 1 diced apple – so together I had 2 cups of mixed fruit/berries. I cooked this apple briefly in sugar and lemon juice – to get rid of extra moisture. After some liquid evaporated, I mixed in starch and blueberries. 
    The crust/topping were made exactly as in your recipe and it is to die for – :) Will definitely make it again, whenever I have leftover berries. 

  24. My husband RAVED about these bars for weeks, it was almost concerning. Super simple recipe that is super delicious. We inherited 14 huge blueberry bushes with our new house, so this recipe will be with us for a long time. Wouldn’t change a thing! Thank you for sharing it.

    • Thanks for trying the recipe and I’m glad it came out great for you!

      I am super jealous of your blueberry bushes! I just moved into a new house in San Diego (where anything grows) and I was seriously considering planting blueberry bushes but was very afraid they’d just be candy for the birds and squirrels! Sounds like it’s possible to have a homegrown crop based on your story!

  25. Loved this recipe! It has become a summer staple with fresh blueberries! I have also tried your other bar recipe (“Berry Crumble Bars”), but I think the oats in this recipe give it a nice texture! I reduced the sugar in the berries to 1/4 cup, since the blueberries I had were on the sweeter side and the recipe was perfect! Thanks for sharing the recipe!

  26. Great recipe!  And they looked just like the picture!!  Will definitely use this recipe over and over. Highly recommend. 

  27. I doubled the receipt using a 9 x 13 dish. 1/2 demerara brown sugar and 1/2 blue agave for the crust along with the packed brown sugar; 1/2 butter and 1/2 coconut oil. The blueberries were out of the frig, not frozen. Checked at 40 minutes and took out at 45. They set up fairly well except around the edges. May be from the agave or may have needed another 5 minutes. I used parchment paper with a little coconut oil on it. Delicious!!! Half in tupperware and half into the freezer :-)

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