Nonstick cooking spray, for the cake pan
One 6-ounce carton vanilla yogurt (reserve the carton for measuring other ingredients)
One 6-ounce carton vegetable oil
One 6-ounce carton granulated sugar
2 large eggs, at room temperature
Two 6-ounce cartons cake flour
One 6-ounce carton unsweetened cocoa
1 1/2 teaspoons vanilla extract
1/2 teaspoon baking soda
1/2 teaspoon baking powder
One 6-ounce carton milk
One 6-ounce carton mini semisweet chocolate chips
Two 6-ounce cartons confectioners' sugar
1 1/2 sticks (12 tablespoons) salted butter, softened
1/2 teaspoon vanilla extract
One 6-ounce carton mini semisweet chocolate chips