Mix protein powder, coconut flour, baking powder, salt, and 1 tablespoon of erythritol.
½ cup unflavored whey/casein protein blend, 2 tablespoons coconut flour, ½ teaspoon baking powder, a pinch of sea salt, 1 tablespoon granulated erythritol
Add lemon zest, lemon juice, vanilla, and coconut oil. Mix well. Use your hands to press the dough together.
zest of ½ lemon, 2 -3 tablespoons lemon juice, ½ teaspoon vanilla extract, 2 tablespoons coconut oil
Separate into 8 pieces, and roll each into a ball. Set on a piece of parchment paper.
Pour 1 tablespoon of erythritol on the parchment (not on the cookies).
1 tablespoon granulated erythritol
Press each cookie into the erythritol, flattening it out. Then place the cookie (erythritol side up) onto a parchment-lined cookie sheet.
Bake for about 13 minutes, or until firm.
Enjoy!
Notes
A note about substitutions: because each type of protein powder has a distinct flavor and texture when baked, I would not try substituting different types of protein powders in this recipe. (See my Recipe Basics video for examples of what goes wrong when you use the wrong protein powder.) If you want to make your own whey/casein blend, use 60% whey and 40% casein, as the Quest powder does.