The word “carton” in the title refers to a 6-ounce yogurt carton, which is used to measure most of the ingredients in this easy-to-assemble cake. Just make sure to rinse and dry the carton before using it to measure out the dry ingredients.
Vanilla Buttercream Frosting
Position an oven rack in the middle of the oven and preheat to 350ºF. Spray a 10-inch round cake pan with a layer of nonstick cooking spray.
To a large mixing bowl, add the yogurt, oil and granulated sugar (using the yogurt carton as the measure) and the eggs; beat together with a hand whisk until everything is incorporated and smooth, 1 to 2 minutes.
Next, add the cake flour and cocoa using the carton as the measure, then the vanilla, baking soda and baking powder; beat together until incorporated, 1 to 2 minutes more. Add the milk and mini chocolate chips (using the carton) and mix until incorporated.
Pour the batter into the prepared cake pan and bake until a cake tester inserted into the center of the cake comes out clean, 35 to 40 minutes. Let cool in the cake pan for 30 minutes, then remove the cake to a cooling rack and allow it to cool for another 30 minutes.
Add the confectioners’ sugar (measured in the carton), butter and vanilla to the bowl of an electric mixer fitted with a paddle attachment and beat until smooth and creamy, 2 to 3 minutes. Spread over the top of the cooled cake in a thick layer and sprinkle with the mini chocolate chips (measure in the carton).