1. Preheat oven to 350 degrees Fahrenheit.
2. Grease and flour your favorite cake pan.
3. In large mixing bowl, mix butter and sugar together until smooth and creamy,
4. Slowly add eggs, vanilla and baking powder. Continue to beat until smooth.
5. Add the flour and milk slowly, alternating the milk and flour. Continue to mix cake batter just until all ingredients are mixed.
6. Add cake batter to your greased cake pan and bake 22-25 minutes or until cake is golden brown and a toothpick inserted in the middle of the cake comes out clean.
7. Remove from oven and let completely cool before frosting.

For the frosting

1. Place all ingredients except the melted chocolate in medium bowl and mix on medium speed with electric mixture until smooth.
2. Add melted chocolate and mix again until frosting is smooth.
3. Decorate cake as desired and add marshmallows for a fun topping!