Place the cottage cheese, egg, vanilla extract, and sweetener into a high-speed blender. Blend on high for 30 seconds until the mixture is completely smooth and no cottage cheese curds remain. This step is crucial for achieving a traditional donut texture rather than a lumpy one.

Pour the blended liquid into a small mixing bowl. Gently fold in the protein powder, almond flour, and baking powder. Stir with a spatula until just combined. Do not overmix, as this can make the donuts tough. The batter should be thick but pourable.

Preheat your oven to 350°F (175°C). Lightly grease a silicone donut pan with non-stick cooking spray. Spoon the batter evenly into the cavities, filling them about three-quarters of the way to allow for rising. Bake for 15 minutes or until the tops are golden brown and spring back when touched.

Remove the pan from the oven and let the donuts cool completely in the mold. This allows them to set so they don’t break when you pop them out. Once cool, remove them and top with a dusting of cinnamon or a simple glaze made from powdered erythritol and a splash of almond milk.