Easiest moist cake recipe

This is pretty much the cake recipe I use every time. It never fails. It stays so incredibly moist, and it's firm enough to carve and stack. Mix a cake mix according to the box directions. Then add: 1 small box of instant pudding (any flavor that matches the cake) and an extra 1/4 C water and an extra 1/3 C vegetable oil. Also add 2 tbsp flour. This makes the cake firmer for carving without affecting the flavor. So there you have it, my secret recipe :)