Oatmeal Cream Pie Cookie Bars
Total Time
50 minutes + 1 hour cooling
Prep Time
30 minutes
Cook Time
20 minutes
Rating
5 out of 5 stars
(0)
Ingredients
8-10 bars
- 1/2 cup (110g) unsalted butter, room temp
- 1/2 cup (100g) light brown sugar, tightly packed
- 1/4 cup (50g) granulated sugar
- 1 large egg, room temp
- 1 tsp vanilla extract
- 1/2 cup + 2 tbsp (80g) all purpose flour
- 1 tbsp cornstarch
- 1 cup (100g) old fashioned rolled oats
- 1/2 cup (50g) quick oats
- 1/2 tsp baking soda
- 1/2 tsp cinnamon
- 1/2 tsp salt
- 1/2 cup (110g) unsalted butter, room temp
- 1/2 cup (100g) vegetable shortening
- 4–5 cups powdered sugar
- 2–3 tbsp milk
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Preparation
Step 1
Preheat the oven to 350F and prepare 2 8″ round cake pans. Coat the inside with a layer of nonstick spray and place a round sheet of parchment paper on the bottom of each pan.
Step 2
In a medium bowl, whisk together the flour, cornstarch, oats, baking soda, cinnamon, and salt. Set aside.
Step 3
In a large bowl using a hand or stand mixer with the paddle attachment, cream together the butter and sugars until light and fluffy (about 2 minutes on medium-high speed).
Step 4
Add in the egg and vanilla and mix on medium-high speed again for about 2 minutes.
Step 5
Mix in the dry ingredients in two parts to not overwhelm the batter. Mix JUST until all of the ingredients are combined. Do not over mix.
Step 6
Split the dough between the two pans and spread it even.
Step 7
Bake for 20-22 minutes or until the edges are a light golden brown.
Step 8
Place the pans on a cooling rack and allow the cookies to cool for at least 30 minutes, or until the pans are no longer warm to the touch.
Step 9
Run a knife around the edge of each cookie, turn them out onto your wire cooling rack and place the cookies in the refrigerator to chill firm (about 45 minutes).
Step 10
While the cookies chill, make the buttercream.
Step 11
In a bowl using a hand or stand mixer with the whisk attachment, mix the butter and shortening until smooth.
Step 12
Mix in the powdered sugar, one cup at a time. As it begins to thicken, mix in the milk 1 tablespoon at a time in between each cup of powdered sugar.
Step 13
The buttercream should be fairly thick but easy to spread. Place the buttercream in the refrigerator to chill for about 20 minutes.
Step 14
To assemble, place one cookie upside-down and peel back the paper. Place the buttercream in a piping bag fitted with a larger round tip, or in a ziplock bag with a corner snipped off. Pipe the buttercream in an even layer on top of the cookie.
Step 15
Place the other cookie right-side up on top of the buttercream, remembering to peel back the paper beforehand!
Step 16
By now, the cookies should be cold but soft enough to slice, and the buttercream should still be cold and thick making these bars easy to slice. I recommend using a serrated knife to saw into the firm crust edges before slicing all the way down into the bars. This stops the buttercream from smooshing out the sides.
Step 17
Store your oatmeal cream pie bars in the refrigerator but allow to come up to room temp before eating. Enjoy!
Step 18
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Chef's notes
You can also use 9 inch pans, just keep an eye on the cookies as they may bake a few minutes faster. If you have them, you can also use 2 8″ square baking pans. And although I haven’t tested it, you can try baking the dough in a single layer in a 9×13″ pan and then cut the cookie in half to sandwich the buttercream in the center.
If you don’t have both types of oats, you can either use all old fashioned or all quick oats, although I recommend the ratio I have in this recipe. All old fashioned will give you a chunkier texture and all quick oats will give you a more smooth texture.
You can also use all butter if preferred. Vegetable shortening is used to give it that classic oatmeal cream pie filling texture, just like Little Debbie.
