Preheat the oven to 350°F.
Sift the protein powders, almond flour, baking powder, cinnamon, and salt into a large bowl.
In another bowl, whisk together the eggs and vanilla extract until well combined.
In a separate large bowl with a hand mixer, or in the bowl of a tabletop mixer, cream the butter, granulated erythritol, and sucralose. With the mixer running, slowly add the egg mixture and beat until smooth. With the mixer still running, slowly add the dry ingredients and beat until smooth and homogeneous, then fold in the macadamia nuts.
Pour the batter into the doughnut pans, filling the cavities three-quarters full. Bake for 9 to 11 minutes, until a toothpick inserted into a doughnut comes out clean.
Remove the keto powdered donuts from the pan, place on a cooling rack, and allow to cool for about 20 minutes. Once cool, put the powdered erythritol in a medium-sized bowl and toss the doughnuts one at a time in the sweetener until fully coated.
Store your keto powdered donuts in an airtight container in the refrigerator for up to 4 days.
