Run a knife around the edge to loosen the cake, then flip it out onto a cooling rack to cool completely.
Method Without Baking Powder:
Whip Egg Whites:
Separate the 4 eggs, placing the whites in a medium bowl.
Whip the egg whites to soft peaks.
Prepare the Batter:
Cream the butter, sweetener, and vanilla until light and fluffy.
Add the egg yolks, beating well.
Mix in the ricotta cheese, whole egg, lemon zest, and lemon juice.