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oatmeal cream pie marshmallow filling in a glass baking dish lined with parchement paper

Best Oatmeal Cream Pie Recipe (Marshmallow Filling)

A copy cat recipe of the classic Little Debbie treat that we all know and love! Creamy marshmallow filling sandwiched between two soft and chewy oatmeal cookies, every bite is nostalgic perfection. This homemade verison of our childhood treat is so much better than store-bought!
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Total Time 30 minutes
Servings: 10 Sandwiches
Course: Dessert
Cuisine: American
Ingredients Method Notes

Ingredients
  

Oatmeal pie cookies
  • 1 cup butter* salted, room temperature
  • 2 eggs room temperature
  • 2 tsp vanilla extract
  • 2 cups brown sugar light
  • 2 tbsp molasses
  • 2 tsp cornstarch
  • 1 tsp baking powder
  • ½ tsp baking soda
  • 2½ cup flour
  • 1 cup quick oats
Marshmallow creme filling
  • 7.5 oz fluff
  • ½ cup butter salted, room temperture
  • ⅓ cup shortening
  • 1 tsp vanilla extract
  • 1 cup confectioner's sugar

Method
 

Oatmeal pie cookies
  1. Preheat oven to 350°. Using a hand mixer and a large bowl, or a stand mixer, cream together the butter and sugar on medium-high for 2-3 minutes. Add vanilla, egg, and molasses. Mix on medium-high for another minute.
  2. Sift all dry ingredients into the same bowl. Mix on medium speed until incorporated. Mix in oats.
  3. Using a cookie scoop, place 2 tbsp dough balls on cookie sheet with parchment paper or silicone baking mat. Bake at 350° for 10 minutes. Cookies will be slightly underbaked. Remove from oven and let sit for a 10 minutes until cool enough to move to a cooling rack using a spatula.
Marshmallow creme filling
  1. Once cookies have cooled completly, cream together the butter & shortening on medium-high spead for 2-3 minutes. Add fluff, mix together for 1 additional minute.
  2. Add vanilla and 1 cup of confectioner's sugar, cream together. Add last half cup of sugar until you have the consistency you desire.
  3. Place filling into a piping bag, and pipe onto half of the cookies, bottom-side up. Top with the remaining cookies to make sandwiches.

Notes

*The butter should be a cool room temperature, but not soft. If the butter is too soft, the cookies will spread too much. Remove butter from the fridge 1-2 hours before baking. To check the softeness, you can push your finger into the butter, it should create an indent, but your finger should not easily sink down into the butter, or slide down the stick. It should still be solid and cool to the touch, and not shiny.