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

To prepare the cottage cheese, simply tilt the container to pour off any excess liquid, or use a fine-mesh strainer if needed. If the cottage cheese is already thick, you can go ahead and blend it directly.

Blend the drained cottage cheese using a food processor or immersion blender until it becomes completely smooth.

In a separate clean, dry bowl, beat the egg whites together with the cream of tartar until stiff peaks form—this step is key to achieving the fluffy, cloud-like texture.

In another bowl, whisk together the egg yolks, smooth cottage cheese, vanilla extract (if using), lemon zest (if using), sweetener, and cornstarch until the mixture is smooth and well combined.

Carefully fold the yolk mixture into the whipped egg whites using a spatula, taking care not to deflate the airy structure you’ve built.

Gently fold in the blueberries, distributing them evenly throughout the batter without breaking the air bubbles.

Using a ¼ cup measuring cup, scoop the batter onto the parchment-lined baking sheet, leaving about 2 inches between each mound.

Bake in the preheated oven for 25 to 30 minutes, or until the tops are golden brown and feel set to the touch.

Allow the cloud bread to cool on the tray for a few minutes before transferring them to a cooling rack. Don’t worry if they seem a bit soft when you take them out—the texture will firm up beautifully as they cool.