Preheat oven to 180°C (360°F).
In a large mixing bowl add 1 egg, nut butter, coconut sugar vanilla extract and salt. Using a fork or whisk, stir the wet mixture for a couple of minutes until all is well combined.
Once smooth, sift into the mixture the protein powder, cocoa powder, 20 grams (1/4 cup) of oat flour and baking powder. Mix until you get a smooth cookie dough, adjusting with more oat flour if the mixture is too sticky .
Refrigerate the dough for at least 15 minutes.
Scoop out some dough and shape the cookies. Transfer the protein brownie cookies to a parchment paper covered baking sheet, spacing them apart, and top with chocolate chips if you want.
Bake these protein chocolate cookies in hot oven for 7 to 12 minutes. Make sure that you the cookies otherwise they will get dry.