Mississippi Mud

Ingredients

• 2 cups all-purpose flour
• 1 1/2 cups granulated sugar
• 1/2 cup light brown sugar, packed
• 3/4 cup unsweetened cocoa powder
• 2 teaspoons baking powder
• 1 1/2 teaspoons baking soda
• 3/4 teaspoon salt
• 3/4 cup canola or vegetable oil
• 2 eggs
• 1 teaspoon vanilla extract
• 6 tablespoons milk
• 1/3 cup sour cream
• 1 cup water, boiling
• 1 (10.5 ounce) package mini marshmallows
• 1/2 cup butter
• 3 tablespoons unsweetened cocoa powder, generous
• 3 cups powdered sugar