Chocolate banana cake with chocolate ganache frosting

Ingredients

• CAKE
• 1 3/4 cups white sugar
• 1 3/4 cups all-purpose flour
• 3/4 cup cocoa powder
• 1 1/2 tsp baking powder
• 1 1/2 tsp baking soda
• 1/2 tsp salt
• 2 eggs
• 1 cup mashed bananas (but i used four medium sized bananas -- more than a cup)
• 1 cup warm water
• 1/2 cup milk
• 1/2 cup canola oil
• 1 1/2 tsp vanilla extract
• CHOCOLATE GANACHE FROSTING
• 8 ounce semi-sweet or bittersweet chocolate
• 3/4 cup cream
• 1 tbsp butter (unsalted)