Line an 8 x 8-inch baking tray with baking paper, grease it and set aside.
In a large mixing bowl, combine the coconut flour and protein powder and mix well. If using the optional nut butter, add that in now.
Using a 1/4 cup at a time, add your milk of choice until a very thick batter is formed.
Transfer the batter to the lined pan and press firmly in place. Top with optional chocolate chips and refrigerate for at least 30 minutes. Slice into bars and keep refrigerated.
Notes
TO STORE: Leftover bars should be stored in an airtight container in the fridge for up to one week. TO FREEZE: Wrap bars in parchment paper, place them in a freezer bag and freeze them for up to three months. Allow the bars to sit at room temperature for 10 minutes before eating.