Move over Little Debbie, we're making our own oatmeal cream pies at home! Our soft and chewy oatmeal cookies are sandwiched together with a buttery marshmallow filling.
Preheat oven to 350°F. Line two baking sheets with parchment paper or silicone baking mats.
In a large mixing bowl, cream together 1 cup salted butter, 3/4 cup light brown sugar, and 1/2 cup granulated sugar using a hand mixer or stand mixer until light and fluffy.
Beat in 2 large eggs and 2 teaspoons vanilla extract until just combined, about 30 seconds.
Add in 2 cups all-purpose flour, 2 teaspoons ground cinnamon (if using), 1 teaspoon baking powder, 1 teaspoon baking soda, and 1/2 teaspoon salt. Mix until combined.
Stir in 2 cups quick oats until well combined.
Scoop dough into 2 inch balls and place onto the prepared baking sheets. Sprinkle with a kiss of sugar if desired. There should be 12 cookie dough balls per pan.
Bake in the 350°F oven until the tops are golden brown, about 10-12 minutes.
Let cool on the baking sheets for 15 minutes before serving warm, or transfer to a wire rack to cool completely.
Cream Filling:
In a large mixing bowl, use a hand mixer to beat 1/2 cup salted butter until light and fluffy, about 2-3 minutes.
Beat in 1 teaspoon vanilla extract until combined and smooth.
Beat in 2 cups powdered sugar, a half cup at a time, mixing in between additions until smooth. After adding in the first 1 cup, add in 2 teaspoons milk and whip until smooth before adding in the final 1/2 cup of powdered sugar.
Stir in 2 cups marshmallow cream until well combined.
Pipe or spread the cream filling onto the cooled oatmeal cookies and enjoy!
Notes
For 20 smaller sandwich cookies: scoop 1-inch dough balls. Use a tablespoon or small cookie scoop to measure. Reduce the baking time to about 8 minutes. You'll bake 40 cookies total to create 20 cream pies.