I'd love to share it @creativewoman!

Ingredients

Chocolate Cake:
1 cup vegetable oil
1/2 cup (1 stick) butter, melted
1/2 cup water
1/2 cup milk
3 eggs, beaten
2 cups sugar
1 teaspoon vanilla extract
1 teaspoon baking soda
1/2 teaspoon salt
2/3 cup cocoa
2 cups flour
Chocolate Frosting:
4 cups powdered sugar
1/2 cup (1 stick) butter, softened
1/3 cup milk
1 teaspoon vanilla extract
1/4 teaspoon salt
2/3 cup cocoa powder
2 1/2 cups mini marshmallows (I used homemade)
Optional: 50g dark chocolate and 1 tablespoon butter for drizzling on top of cake

Instructions

1. Heat oven to 350 degrees F (180 C). Grease and flour three 9 - inch round cake pans.
   In large mixing bowl,beat butter, sugar, and oil until smooth. Add milk, eggs, and water and beat well. Add all other ingredients for cake and stir until combined.
2. Pour batter into prepared pans and bake for 30 - 40 minutes or until toothpick comes out clean.
   Remove from oven and to cooling rack and cool for about 30 minutes then loosen cake edges from pan with a butter knife. Invert onto plates or trays to finish cooling.
3. To prepare the frosting, beat butter until creamy then add powdered sugar one cup at a time until creamed. Add the rest of the ingredients and whip until fluffy.
4. To assemble cake, place one of the cakes on a rotating cake stand or serving plate and spread a thin layer of frosting on top. Top with marshmallows to make even layer. Repeat last step for next layer, then place last cake on top and top with remaining frosting. Use a cake spatula to spread on sides and completely cover cake with frosting. Top with remaining marshmallows. If desired, melt chocolate and butter and place in piping bag to drizzle over cake for a pretty presentation.