A classic and easy Mississippi Mud Cake recipe! It's a moist chocolate sheet cake with marshmallow crème and chocolate frosting on top. An incredibly rich and decadent treat!
Add half of the milk, about 3-4 tablespoons. Add the remaining 2 cups of powdered sugar, and beat well. Add more milk as necessary to reach the consistency you like.
When the cake is done, remove from the oven and immediately spread the marshmallow creme over the top. (see note)
Spread the frosting over the warm cake and marshmallow creme. Use a spatula or knife to swirl it.
I like to serve this cake warm, but it is quite messy. It will set up as it reaches room temperature.
Notes
I find it much easier to warm up the marshmallow creme before spreading it on the cake. Remove the lid and all traces of the foil, and microwave for 15-25 seconds until it has started to puff up over the edge of the jar. Then take it out and spread. So much easier!