Prepare: Preheat oven to 325°F (165°C). Line the bottom of a 7–8 inch springform pan with parchment paper.
Blend: Add egg yolks, cottage cheese, sweetener, vanilla, cornstarch, and baking powder to a blender. Blend until completely smooth.
Whip: In a separate bowl, beat the egg whites with a pinch of salt until they form stiff peaks.
Combine: Gently fold the whipped egg whites into the cottage-cheese mixture in 2–3 additions. Don't overmix—you want to keep the batter airy.
Bake: Pour into the prepared pan and bake for 40–50 minutes, until the top is lightly golden and the center is set.
Cool: Turn off the oven and leave the cake inside with the door slightly open for about 15 minutes. Then cool completely before removing from the pan.
Finish: Dust with a little powdered sugar-free sweetener if desired.
