- 1 box chocolate cake mix, prepared according to package instructions
- 1/3 cup butter
- 1/3 cup milk
- 1/3 cup cocoa powder
- 3 cups powdered sugar
- 10.5 ounce bag mini marshmallows
- Bake chocolate cake in a 9x13 baking dish according to package instructions.
- While the cake bakes, make the chocolate frosting. In a small saucepan over medium-high heat, melt butter. Whisk in milk and cocoa butter. Cook for 2 to 3 minutes, stirring constantly until mixture is fully combined and has slightly thickened. Remove from heat.
- Gradually beat powdered sugar into chocolate mixture until frosting is smooth.
- Pour marshmallows and chocolate frosting over baked cake. Bake at 350 degrees Fahrenheit for 2 to 3 minutes, or until marshmallows has lightly puffed.
- Serve warm and enjoy!