Combine coconut flour, protein powder, baking soda, and salt in mixing bowl
Add in egg yolks, butter, vanilla, coconut oil, and stevia and mix with hand mixer until combined (may need to mash together with hands and then use mixer again if not combining well)
Lay a piece of plastic wrap onto counter and place dough it
Form a rectangular log that is 20 cm long
Wrap plastic wrap around log and place in refrigerator for 30 minutes
Preheat oven to 350 degrees
Remove dough log from refrigerator and slice into 20 cookies, 1 cm thick each
Place on parchment lined cookie sheet
Bake for 12-14 minutes or until slightly browned around edges
Remove from oven and allow to cool on cookie sheet for 10 minutes