Oatmeal cream pie bars will remind you of the oatmeal creme pies you used to get in your lunchbox. These chewy cookie bars are super easy to make and will give you a taste of childhood.
Chewy oatmeal cookie bars are rich with deep molasses flavor and topped with marshmallow fluff buttercream for the perfect treat. These bars come together super quickly, they can be in the oven in under 10 minutes.
Then a quick marshmallow frosting layer is spread over to make them out of this world good. They are just like those Little Debbie treats we all grew up on!
If these don’t bring back childhood memories of sack lunches, I don’t know what will. Actually, to tell you the truth I am not sure that I frequently had these in my lunch box.
I seem to think I ate school lunch most of the time. Though I do know that when I was older, my mom always had a treat basket for my younger siblings’ lunches.
They seemed to bring cold lunch more often and they got to pick one item from the treat basket for their lunch box. Of course the treats were the best part of the lunch packing (and eating) experience!
Why We Love These Cookie Bars
These cookie bars are easy to make. You don’t have to worry about them spreading, so you can start with melted butter and soft dough.
You can mix it by hand with no problem, no need to pull out the stand mixer or anything! Just spread it, bake it and load it with frosting!
There is the warm depth of molasses and just a slight cinnamon spice. It is a great compliment to the marshmallow fluff buttercream frosting.
In fact, the molasses and creamy frosting combine to make almost a caramel flavor. And the chew of the cookie is so good.
I originally shared this recipe here on the site back in 2016. I made them for a football party and they were a hit.
But most of you didn’t know I existed back in 2016 and I have been dreaming of these bars for the past couple of months. So I whipped some up, shot some new pictures and a video and added a printable recipe card so you could more easily make them too.
And I really hope you do. These went with me to family dinner and everyone kept going back for a little more.
They also lead to a lot of fun conversation about our favorite packaged treats. What are your favorite convenience treats?
It would be fun to make more copycat versions of stuff. Just let me know what you’d like and we’ll see what we can come up with!
Storing Oatmeal Cookie Bars
These cookie bars can be stored at room temperature for a couple of days. They are at their chewy best when stored at room temperature.
For longer storage, refrigerate in an airtight container for up to a week. Or freeze them for up to three months.
If you chill them until the frosting is set, you can stack them for storage. But I would but them in a single layer to defrost them.
My guess is they won’t last that long anyway. They are super tasty and hard to stay out of once you dig in!
More fun cookie bar recipes
If you are a fan of soft and delicious cookie bars, you may want to check out my recipe for soft sugar cookie bars. I topped mine with a chocolate frosting and plenty of sprinkles for a fun treat!
Or for a fun fall flavored treat, make some pumpkin spice cookie bars. They are another fabulous option to go with the marshmallow fluff buttercream!
Blondies are a quick and easy way to get sweets to the masses. The recipe for chewy caramel and candy blondies are a fabulous large batch treat for parties.
Love this recipe? Give it a ⭐⭐⭐⭐⭐ review in the recipe card below!
- 1 cup butter, melted
- 2 cups brown sugar
- 4 Tablespoons molasses
- 1 Tablespoon vanilla
- 2 eggs
- 1 teaspoon cinnamon
- 1/2 teaspoon salt
- 2 cups instant oats
- 1 1/2 cups flour
- 1 teaspoon baking powder
- 1 recipe marshmallow fluff buttercream
- Preheat oven to 350°F and grease a 10x15-inch bar pan.
- Stir together butter, brown sugar, molasses and vanilla. Add eggs and mix well.
- In another bowl, stir together dry ingredients.
- Add dry ingredients to wet ingredients, stirring until just combined.
- Spread in prepared pan and bake for 25-30 minutes or until set.
- Allow to cool and spread with frosting.
- Cut into squares and serve.
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Amount Per Serving: Calories: 205Total Fat: 9gSaturated Fat: 5gTrans Fat: 0gUnsaturated Fat: 3gCholesterol: 37mgSodium: 138mgCarbohydrates: 29gFiber: 1gSugar: 19gProtein: 2g
All nutritional information is estimated and will depend on the exact ingredients you use.