Iced Oatmeal Cookie Bars (Little Debbie Copycat!) — The flavor of the classic cookies turned into fast, easy, chewy bars and the frosting is beyond amazing! They’re even better than original Oatmeal Creme Pies!!
Little Debbie Oatmeal Creme Pies were some of my favorite cookies growing up and I could eat a box in a day.
But these iced oatmeal bars are even better.
In doing research for this recipe, I bought a box of Oatmeal Creme Pies. It had been nearly 20 years since I last tried them and unfortunately what I bit into didn’t match my beloved memories. I made it my mission to create a new oatmeal creme cookie recipe that’s worth biting into and I think is better than the original.
I have so many oatmeal cookie recipes because when oatmeal cookies are done right — and by that I mean soft, chewy, and not over-baked — they’re some of my favorites. The chewiness, the perfectly hearty texture, and the nuttiness of the oats speak to me.
Rather than go to the fussiness of making sandwich cookies to recreate the classic Little Debbie cookies, I made bars. Bars are so much faster and easier than cookies since there’s no dough to chill and nothing individual to roll.
The bars are soft, very chewy from the oats, not at all cakey, and perfectly dense. It’s one-bowl, no-mixer batter and you’ll have it from the bowl and into the oven in less than five minutes with only one bowl to wash. Love that.
The icing is buttercream frosting spiked with a jar of marshmallow creme and makes the bars taste truly authentic. It’s sweet, decadent, soft, fluffy, sticky, rich, and you’ll want to eat it by the spoonful.
Ingredients for Iced Oatmeal Cookie Bars
To make this easy recipe for oatmeal bar cookies, you’ll need:
- Brown sugar
- Vanilla extract
- Instant oats
- All-purpose flour
- Confectioners’ sugar
- Marshmallow Creme
How to Make Iced Oatmeal Cookie Bars
Making oatmeal bar cookies is even easier than making regular cookies because there’s no dough to chill or roll into balls. Win!
Here’s an overview of how the cookie bars are made:
- Make the bars: Whisk together the melted butter, egg, brown sugar, molasses, cinnamon, salt, and vanilla.
- Add the oats and flour. Stir only until combined.
- Turn the dough into a foil-lined 8×8-inch baking dish.
- Bake the bars until a toothpick inserted in the center comes out clean.
- Make the icing: In a separate bowl, beat the butter and confectioners’ sugar until light and fluffy.
- Add the marshmallow creme and salt and beat until combined.
- Once the cookie bars have cooled completely, top with icing.
Can This Recipe Be Doubled?
Yes! Double the ingredients and bake the oatmeal cookie bars in a 9×13-inch pan.
Can This Recipe Be Made in Advance?
Yes! You can prepare the entire recipe as written a day before serving, or you can store the bars on your counter and pop the icing in the fridge until you’re ready to ice and serve.
Tips for Making Iced Oatmeal Bars
- Use quick-cook oats rather than old-fashioned for the perfect amount of chewiness.
- You’re welcome to add more cinnamon to the bars if you’d like a more pronounced cinnamon flavor.
- You can halve the frosting portion if you’re not a huge frosting person, but I am. The more, the merrier!
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Iced Oatmeal Cookie Bars (Little Debbie Copycat!)
The flavor of the classic cookies turned into fast, easy, chewy bars and the frosting is beyond amazing! They're even better than original!
- 1/2 cup unsalted butter, melted
- 1 large egg
- 1 cup light brown sugar, packed
- 2 tablespoons medium, dark, or full-bodied molasses
- 1 tablespoon vanilla extract
- 1/2 teaspoon salt
- 1/4 teaspoon cinnamon
- 1 cup instant oats (not old-fashioned or whole-rolled)
- 3/4 cup all-purpose flour
- 1/2 cup unsalted butter, softened
- 1 1/2 cups confectioners’ sugar
- one 7-ounce jar marshmallow creme
- 1/4 to 1/2 teaspoon salt (cuts some of the sweetness)
- Preheat oven to 350F. Line an 8-by-8-inch baking pan with aluminum foil, spray with cooking spray; set aside.
- In a large, microwave-safe bowl melt the butter, about 1 minute on high power.
- Wait momentarily before adding the egg so you don’t scramble it. Add the egg, brown sugar, molasses, vanilla, salt, cinnamon, and whisk until smooth.
- Add the oats and stir to combine.
- Add the flour and stir until just combined, don’t overmix.
- Turn batter out into prepared pan, smoothing the top lightly with a spatula. Bake for about 24 to 25 minutes, or until done. A toothpick inserted in the center should come out clean, or with a few moist crumbs, but no batter.
- Place pan on top of a wire rack to cool completely before frosting. Don’t frost warm bars or the frosting will melt.
- To the bowl of a stand mixer fitted with the paddle attachment (or large bowl and electric hand mixer), add the butter, confectioners’ sugar, and beat on medium-high speed (start on low so you don’t spray sugar everywhere) until light and fluffy, about 3 minutes.
- Stop, scrape down the sides of the bowl, and add the marshmallow creme, salt, and beat on medium-high speed until well combined, about 1 minute.
- Turn frosting out over bars and lightly smooth it with a spatula or offset knife.
Storage: Bars will keep airtight at room temperature for up to 5 days. I’m comfortable storing buttercream-style frosting at room temp but if you’re not, refrigerate the bars noting they’ll be more prone to drying out in the fridge.
Amount Per Serving: Calories: 368Total Fat: 16gSaturated Fat: 10gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 56mgSodium: 203mgCarbohydrates: 54gFiber: 1gSugar: 39gProtein: 3g
More Oatmeal Cookie Recipes:
Iced Pumpkin Oatmeal Cookies — Soft and pillowy pumpkin cookies that are chock full of pumpkin spice and everything nice! The icing takes these cookies over the top.
The Best Oatmeal Chocolate Chip Cookies – Soft, chewy, loaded with chocolate, and they turn out perfectly every time! Totally irresistible!
Loaded Oatmeal Chocolate Chip Cookies — Soft, chewy, and loaded with chocolate! Sinking your teeth into a thick, hearty cookie is the best!! So good!
Soft and Chewy Oatmeal Coconut Chocolate Chip Cookies – No butter and no mixer used in these easy cookies dripping with chocolate!
Soft and Chewy Oatmeal Scotchies Cookies – My favorite classic oatmeal cookie base loaded with sweet butterscotch chips! A classic cookie that you’ve just got to try!
These were so good! Big hit both times I brought them. I’m thinking next time I might just make a second batch of the cookie part and make a giant sandwich and cut into squares.
Thanks for the 5 star review and glad you’ve made them twice already! Great idea for the future, too.
Hello, I would like to thank you for your amazing and awesome blog. That is totally awesome. I also made it at home and your recipe is too good. Please update me if you update the new recipe. I loved it very much. Thank you so much for the lovly blog.
There’s an email signup for recipes at the top of every page. HUGE. Enter your email address if you want free recipes.
Thanks for trying the recipe and I’m glad it came out great for you!
Making these today. I have homemade buttercream frosting leftover from my son’s birthday cake.
Perfect timing with your leftover buttercream – enjoy!
looks like tasty and funny “creme pie cookie bars”. Enjoy!!
Yummy and tasty creme pie cookie bars. my all time favorite.
Wow this recipe is life changing, absolutely delicious! I used 2 5″ round cake pans and made it into a GIANT oatmeal creme pie for my husband! Thanks!
I love your idea of making a giant OCP! I love that it’s life changing for you :)
I know you just posted these yesterday, but as soon as I read your post, I knew I had to have them. So I went out to the store today to buy some instant oats, molasses, and marshmallow cream.
I literally love everything on your website and each year I blow out my birthday candles I wish for a friend with have the delicious arsenal of goodies (and non-goodies) you have. Unfortunately, it’s not happening soon. I finally had all the ingredients to make these. It’s been on my to do list for some time., but I can never remember molasses. These are AMAZING. My husband asked why I always am making things. Simple. I know he is going to root through the cabinet later for some prepacked yuck food. I’d rather make these (super easy by the way-yay) and have him eat half a pan, then a box of the chemical laden ones. Thanks for such a delicious recipe. As always YUMMMMMMM
Hi Jen, long time no talk! :) Thanks for saying hi and for trying the recipe and I’m glad it came out great for you! And amen for when we can make things from scratch and save our families from rooting through the cabinets looking for whatever they can scrounge up!
Wow this recipe is life changing! Maybe that’s dramatic, but I adored Oatmeal Creme Pies as a kid. All time favorite after school snack. I made these (twice already) and they are really perfect. I love knowing all the ingredients and making this treat from scratch. You’ve taken my favorite treat and improved it – thanks for sharing!
Thanks for trying the recipe and I’m glad it’s life changing! :) So glad you’re as much of an Oatmeal Creme Pie fan as I am and you prefer this new and improved version :)
it’s loooking so yammy i will try your recipe in my next weekend
i love cookies. you gave me my childhood memoirs. here you give beautiful collection. you brought taste on my tong.
WOW! These are bars are fantastic. I made them this morning, according to the recipe, with two exception. I used mild molasses and vanilla bean paste in place of extract. I choose to use a half recipe of the icing and was pleased with the coverage of that amount. This is probably the best recipe I have tried off Pinterest this year. Thanks Averie Sunshine!
Thanks for trying the recipe and I’m glad it came out great for you! I’m glad it’s your favorite Pinterest recipe of the year! Keep me posted if you make other things from my site.
Mine turned out super dark. Maybe not the right molasses? I used the correct amount but they were dark brown. Any suggestions? I love your site and usually everything I try comes out great! Thanks!!!
They look dark (just cosmetic but taste fine) – That would likely be a too-dark molasses, such as blackstrap or sometimes molasses is labeled as dark, or bold.
They taste dark, aka – burnt. That would likely be overbaking. All ovens, climates, ingredients, vary and just reduce baking time next time.
Not sure which is the case and if it’s only cosmetic but they still taste good, now you learned something about molasses for the future :)
I just made this – absolutely delicious! I used 2 6″ round cake pans and made it into a GIANT oatmeal creme pie for my husband! Thanks!
Thanks for trying the recipe and I’m glad it came out great for you! And sounds like your hubby is probably pretty happy right now :)
I made the frosting yesterday to get ahead for a lunch today, and I’m making the bars today. Well, I’m glad I made the full frosting recipe because after a drink or two last night my husband and I smeared so many “tastes” of this frosting onto strawberries and some lemon bars that it’s like 1/2 gone…annnddd I’m not a huge frosting person. Can’t wait for the bars!
Thanks for trying the recipe and I’m glad the frosting was so good on the berries and the tastes along the way ;) After a few drinks, I have no willpower and just would have ate the whole thing! Enjoy the bars :)
I remember these oatmeal creme pies when I was a kid, they were one of my favorites. These bars look soooo good!
I made these last weekend for a family dinner and they were FANTASTIC! Everyone raved about them. Will definitely make again!
Thanks for trying the recipe and I’m glad it came out great for you and that they got rave reviews and you’ll make again!
These look amazing! My husband would absolutely love these!
I know you just posted these yesterday, but as soon as I read your post, I knew I had to have them. So I went out to the store today to buy some instant oats, molasses, and marshmallow cream. And here I am eating some amaaazing warm oatmeal bars (no icing yet because I couldn’t wait)! Thanks for the great recipe!
Thanks for trying the recipe and I’m glad it came out great for you even without the icing (which is the BEST PART…haha!) Hope you got to add that and thanks for trying the recipe the day I made it!
These look devine! I think the bars actually look better :)
Little Debbies were my childhood! I loved oatmeal cream pies, and you’re right, they don’t taste the same. I’m totally making this for the kids though, they’d love them!
My husband loves Oatmeal Cream Pies, but I never “let” him get them from the store. Preservatives and all that. This dessert looks like a fantastic alternative, and I love that you made them easier to prepare by going with a bar. Thanks for the recipe, Averie!
Averie I have never eaten oatmeal creme pie before!! I know I am missing out on such a dreamy treat! Thanks to your recipe I will be trying it out soon!
I don’t think I’ve ever had a Little Debbie cream pie (!!!!) but I know I could eat ALL of these bars straight from the pan with a fork!
See that pic with the fork mark, that wasn’t ‘staged’. I had to donate these, promptly :)
Wow, these look so good!
These look so good!
I love all your amazing copycat recipes! I feel so much better about food when I know exactly what goes into it!
I ca totally see how you can eat a box of those a day, your homemade version looks so much better now I can eat a pan of these a day, easilyyyyyy!
I never tried Little Debbies, but these look good. We had a similar disappointing experience with store bought iced circus animal cookies recently! I don’t know if they tasted that bad when we were kids and we didn’t notice or if they’ve lost quality over the years. It’s good to know how to bake!
That’s so funny about the circus animal cookies b/c I loved those things as a kid too! And once when my daughter was a toddler I bought her some of those and had one…blech! Not the same at all as my glowing memories of them :) Same as your experience!
I was such a lover of those oatmeal creme pies too! Such a treat to get one in my lunchbox at school. Loving how these aren’t fussy and easy to make in a bar form. Delicious :)
Oatmeal creme pies and nutty bars were my favorites in high school and I’m sorry to hear the creme pies aren’t the same these days. I remember the marshmallowy middle and something different about the flavor of the cookie ( but never thought about what it might be). Now I realize it had to be the molasses. It looks like you have nailed this one! Homemade always seems to taste better anyway.☺
The molasses is huge in these…and most storebought things are skimpy on it, I’ve determined! And the disappointment that I had after buying a box of OCP’s recently and trying them, not the same at all as what I remember! I loved Nutty Bars too and was recently tempted to buy a box of those but after my last OCP attempt, I thought better of it :)
Isn’t it funny how the food we LOVED as kids is never the same when we try it as adults? The real thing just can’t compete with those happy memories.
I have a lot of nostalgia with these, too. I ate one every day in high school instead of lunch. Not healthy, but so much fun!
Your version looks much better, though. I’m into all that frosting! And it’s not made with hydrogenated anything.
The real thing just can’t compete with those happy memories. <---- Isn't that the truth!! I should have just let those happy memories live in peace and never taken another bite as an adult :)
looks devine!!!! yumm