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!)
- ½ 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
- ½ teaspoon salt
- ¼ teaspoon cinnamon
- 1 cup instant oats, not old-fashioned or whole-rolled
- ¾ cup all-purpose flour
- ½ cup unsalted butter, softened
- 1 ½ cups confectioners’ sugar
- one 7-ounce jar marshmallow creme
- ¼ to ½ 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.
Nutrition information is automatically calculated, so should only be used as an approximation.
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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!