Super-Moist Chocolate Cake with Chocolate Buttercream Frosting

INGREDIENTS

Eggs, large

1 1/3 cups

Mayonnaise

2 3/4 cups

All purpose flour

1/4 tsp

Baking powder

1 1/4 tsp

Baking soda

2 oz

Bittersweet chocolate

1 cup

Brown sugar, dark packed

3/4 cup

Cocoa powder, unsweetened

1 cup

Hershey's special dark cocoa powder, unsweetened

4 1/2 cups

Powdered sugar

1 cup

Sugar

4 tsp

Vanilla

1 1/4 cups

Butter

3/8 cup

Milk or heavy cream

1 3/4 cups

Water