Go Back

Oatmeal Cream Pie Cake

Oatmeal Cream Pie Cake features tender oatmeal spice cake layers stacked with a thick, marshmallow cream filling for a soft, sliceable dessert. The frosting is beaten until very fluffy and spread between layers and over the outside.
Print Recipe Pin Recipe
Prep Time 35 minutes
Cook Time 35 minutes
Total Time 1 hour 10 minutes
Servings: 12 servings
Course: Dessert
Cuisine: American
Calories: 520
Ingredients Equipment Method Notes

Ingredients
  

For oatmeal cake layers
  • 2 cup flour
  • 1.5 cup rolled oats
  • 1 tsp baking powder
  • 0.5 tsp baking soda
  • 2 tsp cinnamon
  • 0.5 tsp nutmeg
  • 0.5 tsp salt
  • 1 cup butter
  • 1.5 cup brown sugar
  • 4 eggs
  • 1 cup sour cream
  • 2 tsp vanilla
For marshmallow cream filling
  • 0.5 cup unsalted butter
  • 4 oz cream cheese
  • 1 can (7 oz) marshmallow creme
  • 2 cup powdered sugar
  • 1 tsp vanilla

Equipment

  • 2 sheet pan

Method
 

Bake the oatmeal cake layers
  1. Preheat oven to 350F, then grease two 9-inch round pans. Keep them ready so the batter can go in right away.
  2. Beat butter and brown sugar until combined, then add eggs, sour cream, and vanilla. Mix just until the batter looks smooth.
  3. Fold in flour, rolled oats, baking powder, baking soda, cinnamon, nutmeg, and salt. Stop mixing when no dry streaks remain.
  4. Divide batter between the two pans and spread evenly. Bake for 30-35 minutes at 350F, until the centers spring back when touched.
  5. Cool the cakes completely in the pans before filling. This prevents the marshmallow cream from melting or sliding.
Make and spread the marshmallow cream filling
  1. Beat the softened unsalted butter and softened cream cheese until smooth. Scrape the bowl so everything blends evenly.
  2. Add marshmallow creme and beat until thick and creamy. Continue mixing until the filling looks uniform with no lumps.
  3. Beat in powdered sugar and vanilla until very fluffy. Pause to scrape the bowl for a light, spreadable texture.
  4. Frost between the cooled cake layers with the marshmallow cream filling. Use an even layer so the cake holds together when sliced.
  5. Spread the remaining marshmallow cream on the outside of the cake. Smooth the surface and dust lightly with any leftover cinnamon-scented flavor if desired.

Notes

Pro tip: make sure the cake layers are fully cool before assembling—warm cake will cause the marshmallow cream to soften and slide. Store assembled cake in the refrigerator up to 4 days. Freeze unfrosted cake layers up to 2 months; thaw overnight in the fridge, then frost. For a dairy-reduced option, use dairy-free butter and cream cheese, and keep marshmallow creme unchanged.