Preheat oven to 300 degrees Fahrenheit (150 degrees Celsius) and line a heavy-duty baking sheet with parchment paper.

In a high-speed blender, process the cottage cheese, egg yolks, sweetener, and vanilla extract until the mixture is completely homogenous and smooth.

In a separate, grease-free mixing bowl, combine egg whites and cream of tartar.

Whisk egg whites using an electric hand mixer or stand mixer on medium-high speed until stiff, glossy peaks form.

Slowly fold the blended cottage cheese mixture into the egg whites using a silicone spatula, being careful not to deflate the incorporated air.

Gently fold in the fresh blueberries until evenly distributed.

Spoon the mixture into 6 equal circular mounds on the prepared baking sheet, leaving 2 inches of space between each.

Bake for 30 minutes or until the bread is golden brown and the centers are firm to the touch.

Remove from oven and allow the cloud bread to cool completely on the pan before attempting to remove it from the parchment.