Preheat your oven to 350*F and spray a 9x13 baking pan with nonstick spray.
In a large bowl, with a hand mixer, mix together your cake mix according to the directions on the box. Set aside.
In another bowl, using the hand mixer, beat together the ricotta cheese, eggs, sugar, and vanilla until smooth.
Pour the cake batter into the prepared baking dish. Spread to fill the pan evenly. Once the cake batter is in place, carefully pour the cheese mixture evenly over the top of the cake batter. Spread to cover the cake batter as best as you can.
Bake the cake at 350F for 1 hour. Remove from the oven and allow to cool completely before frosting.
Once the cake is cool, stir the pudding mix and milk together with a whisk until combined. Carefully, fold the Cool Whip into the pudding until combined.
Spread the pudding mixture over the top of the cooled cake.
Cover the cake and refrigerate at least 6 hours before serving. I let it refrigerate overnight, it tastes even better the next day.