Hostess Sheet Cake
Learn how to make a delicious Hostess sheet cake with rich chocolate layers, creamy marshmallow frosting, and signature chocolate ganache topping. Perfect for parties!
Equipment
- 9x13 inch baking pan
- large mixing bowl
- whisk
- medium bowl
- spatula
- wire rack
- electric mixer
- heatproof bowl
- small saucepan
- offset spatula
- piping bag
- wooden skewer
- knife
- cutting board
- measuring cups
- measuring spoons
- oven
Ingredients
Chocolate Cake
- 1.75 cups all-purpose flour
- 1.75 cups granulated sugar
- 0.75 cup unsweetened cocoa powder
- 1.5 tsp baking soda
- 1 tsp fine sea salt first measurement
- 0.5 cup unsalted butter softened, first measurement
- 1 cup boiling water
- 0.5 cup buttermilk at room temperature
- 2 large eggs at room temperature
- 1 tsp vanilla extract first measurement
Marshmallow Cream Frosting
- 0.5 cup unsalted butter softened, second measurement
- 1.5 cups powdered sugar sifted
- 7 oz marshmallow fluff
- 2 tbsp whole milk second measurement
- 1 tsp vanilla extract second measurement
- 0.25 tsp fine sea salt second measurement
Chocolate Ganache
- 1 cup semi-sweet chocolate chips
- 0.5 cup heavy cream
- 1 tbsp unsalted butter third measurement
- 0.5 tsp vanilla extract third measurement
- 1 pinch fine sea salt third measurement
Instructions
- Preheat your oven to 350 degrees Fahrenheit. Lightly grease and flour a 9x13-inch baking pan, ensuring the flour evenly coats all surfaces, then tap out any excess. In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, cocoa powder, baking soda, and the first measurement of fine sea salt until well combined and lump-free.
- In a separate medium bowl, melt the first measurement of softened unsalted butter (1/2 cup) with the boiling water. Stir until the butter is fully melted. Allow this mixture to cool slightly for about 5 minutes, then whisk in the buttermilk, eggs, and the first measurement of vanilla extract (1 teaspoon) until smooth.
- Pour the wet ingredients into the dry ingredients and mix with a whisk or spatula until just combined. Be careful not to overmix; a few small lumps are fine. Pour the batter evenly into your prepared 9x13-inch baking pan. Bake for 28 to 32 minutes, or until a wooden skewer inserted into the center of the cake comes out with moist crumbs attached, but no wet batter. Let the cake cool completely in the pan on a wire rack for at least 1 hour.
- While the cake cools, prepare the marshmallow cream frosting. In a large bowl, beat the second measurement of softened unsalted butter (1/2 cup) with an electric mixer on medium speed until creamy, about 2 minutes. Gradually add the sifted powdered sugar and beat until light and fluffy. Add the marshmallow fluff, the second measurement of whole milk (2 tablespoons), the second measurement of vanilla extract (1 teaspoon), and the second measurement of fine sea salt (1/4 teaspoon). Beat on high speed for 3-5 minutes, or until the frosting is light, airy, and well combined.
- Once the cake is completely cool, spread the marshmallow cream frosting evenly over the top of the cake, reserving about 1/4 cup of the frosting for the signature swirl. Place the frosted cake in the refrigerator to chill while you prepare the ganache.
- For the chocolate ganache, place the semi-sweet chocolate chips in a heatproof bowl. In a small saucepan, heat the heavy cream and the third measurement of unsalted butter (1 tablespoon) over medium heat until it just begins to simmer around the edges. Pour the hot cream mixture over the chocolate chips. Let it sit for 5 minutes without stirring.
- After 5 minutes, add the third measurement of vanilla extract (1/2 teaspoon) and the third measurement of fine sea salt (pinch) to the chocolate mixture. Whisk gently from the center outwards until the ganache is completely smooth and shiny. Allow the ganache to cool for 5-10 minutes, or until it's slightly thickened but still pourable.
- Retrieve the frosted cake from the refrigerator. Carefully pour the slightly cooled ganache over the marshmallow frosting, spreading it gently with an offset spatula to cover the entire surface, letting a little drip over the edges. Immediately transfer the reserved 1/4 cup of marshmallow frosting to a small piping bag or a ziploc bag with a tiny corner snipped off. Pipe the iconic white squiggle lines across the width of the cake, then use a wooden skewer or toothpick to drag through the lines in alternating directions to create the classic Hostess pattern. Refrigerate the cake for at least 1 hour to allow the ganache and frosting to set before slicing and serving.
Notes
Ensure all ingredients are at room temperature for best results. Let the cake cool completely before frosting to prevent melting.