This is yet another America's Test Kitchen recipe, and its soooo simple and easy. It reminds me of the cake my grandmother made for us when we were younger, not too sweet but DELICIOUS. You will need a 9-inch nonstick cake pan with sides that are at least 2 inches high for this cake. You make also use a 10-inch ovenproof stainless steel skillet (do NOT use cast iron) to both cook the apples and bake the cake, with the following modifications: Cook the apples in the skillet and set them aside while mixing the batter (it’s OK if the skillet is still warm when the batter is added) and increase the baking time by 7 to 9 minutes. If you don’t have either a 2-inch high cake pan or an ovenproof skillet, use an 8-inch square pan.