Chocolate Coca-Cola Cake

A warm chocolate cake covered with a thick chocolate frosting is a decadent combination.
Combine the first 3 ingredients in a medium saucepan over medium heat, stirring until the butter melts. Remove from heat.Combine the flour, sugar, and baking soda in a large bowl; add the butter mixture. Add the eggs and mix until smooth. Add buttermilk, vanilla and marshmallows.Pour into a lightly greased 13-inch x 9-inch baking dish. Bake at 350 ° C for 25-30 minutes or until a stick inserted in the middle comes out clean. Remove from the oven; spread the warm cake with chocolate icing and Coca-Cola.