Separate the egg whites from the egg yolks
Zest the lemon
Juice the lemon to get 2 TBS of lemon juice
In a large mixing bowl, place the egg whites, gelatin, and egg white powder
With a hand mixer (or stand mixer) whip the egg whites until they form a stiff peak
In a medium bowl, combine the softened butter, ricotta, and sweetener
With a hand mixer, blend until smooth
Add the egg yolks and vanilla to the ricotta mixture and mix well with the hand mixer
Add the ricotta mixture to the egg whites and fold in until it is well combines
Pour into a 9" springform pan
Bake at 350 F for 45 minutes
Let cool
Top with lemon curd, blueberries or powdered sweetener