Preheat your oven to 350°F (180°C) and grease an 8-inch baking dish.

In a clean mixing bowl, whip egg whites and cream of tartar on medium-high until stiff peaks form, about 3-5 minutes.

In another bowl, combine egg yolks, cottage cheese, cornstarch, powdered sweetener, vanilla, and lemon zest. Blend until smooth.

Gently fold the whipped egg whites into the yolk mixture until no white streaks remain.

Fold in the fresh blueberries carefully.

Pour the batter into the prepared dish and smooth the top.

Bake for 25-30 minutes until golden brown and springs back lightly.

Cool completely in the dish before slicing.