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4.75 from 20 votes

Hostess Sheet Cake

This incredibly chocolatey and delicious sheet cake is a take on the nostalgic Hostess cupcake we all grew up eating. The fudge frosting, paired with the creamy marshmallow filling and moist chocolate cake makes for the perfect bite!
Prep Time15 minutes
Cook Time35 minutes
Course: Dessert
Keyword: cake, chocolate, fudge, marshmallow, sheet cake
Servings: 15 slices
Author: Emily - My Messy Kitchen

Ingredients

For the cake:

  • 2 cups granulated sugar
  • ¼ cup salted butter melted
  • ¼ cup vegetable oil
  • 1 tsp vanilla extract
  • 2 eggs room temperature
  • ¾ cup cocoa powder
  • 1 ¾ cup all-purpose flour
  • 2 tsp baking soda
  • 1 ½ tsp baking powder
  • ½ tsp salt
  • 1 cup brewed strong coffee you can also substitute for 1 cup hot water
  • 1 cup whole milk

For the filling:

  • 14 oz marshmallow fluff
  • 1 cup salted butter room temperature
  • 3 ½ cups powdered sugar
  • 2 tsp vanilla extract
  • 2-4 tbsp whole milk or heavy cream room temperature
  • ¼ tsp salt

For the frosting:

  • 1 cup salted butter room temperature
  • 4 ½ cups powdered sugar
  • ¾ cup cocoa powder
  • ½ cup whole milk room temperature
  • 1 tsp vanilla extract
  • ¼ tsp salt

Instructions

For the cake:

  • Preheat the oven to 350° Grease and line a 9x13 metal baking pan with parchment paper and set aside. **See note below on baking in two 9x13 pans if you have them!
  • In the bowl of a stand mixer combine the melted butter, granulated sugar, vegetable oil, vanilla extract and eggs. Mix on medium until combined.
  • In a medium bowl sift cocoa powder, flour, baking soda, baking powder and salt. With the mixer on low, add half of the dry ingredients, then the milk. Add the rest of the dry ingredients and the coffee. Mix until fully incorporated.
  • Pour into the prepared baking pan and bake for 30-35 minutes or until baked through. Remove from the oven and allow to cool for 30 minutes at room temperature before refrigerating until cold, about 1 hour or up to overnight.

For the filling:

  • In the bowl of a stand mixer beat the butter and marshmallow filling until smooth, about 1 minute. Add in the vanilla extract, powdered sugar, salt and milk. Add more milk if needed to reach desired spreading consistency. Set aside until assembly.

For the frosting:

  • In the bowl of a stand mixer cream the butter, powdered sugar and cocoa powder until combined. Add in the vanilla, milk and salt and beat until smooth. Set aside until assembly.

For assembly:

  • Once the cake has completely cooled, flip the cake out of the pan. Use a serrated knife to slice the cake in half length wise, trying to make the cut as even as possible.
  • Place the bottom half of the sheet cake down, then add marshmallow filling, reserving about ½ cup for piping. Evenly spread and top with the other half of the cake. Refrigerate for 30 minutes or up to 1 hour.
  • Remove the cake from the fridge and evenly spread the fudge frosting on the top and sides of the cake.
  • Add extra marshmallow filling to a piping bag fit with a small round tip. Evenly space and pipe 5 small looped lines from one side to the other width wise. Slice and serve! This cake cake be stored at room temperature or refrigerated. See above in the blog post on how I cut this cake and get clean slices every time!

Notes

Baking in two 9x13 pans: If you happen to have two 9x13 inch metal baking pans you can divide the batter in half and avoid needing to cut the cake horizontally. Grease and line the pans with parchment paper and equally divide the batter. Bake for 24 minutes or until baked through.