Preheat the oven to 300°F (150°C) and line a baking sheet with parchment paper.

Drain the full-fat cottage cheese and blend until smooth, then set aside.

In a clean bowl, beat egg whites with cream of tartar until stiff peaks form, about 3–5 minutes.

In another bowl, whisk egg yolks, blended cottage cheese, cornstarch, sweetener, vanilla extract, and lemon zest until smooth.

Gently fold the egg yolk mixture into the whipped egg whites.

Fold in the fresh blueberries until evenly distributed.

Scoop mounds of the batter onto the prepared baking sheet, spacing them apart.

Bake for 25–30 minutes until golden brown and firm to the touch.

Cool on a wire rack for about 10 minutes before serving.