Combine the peanut butter, protein powder and vanilla in a bowl. Stir until fully incorporated and a cookie dough consistency is formed. The batter can be thinned by adding 1 tbsp of non-dairy milk, if needed.
Line a sheet pan with parchment paper. Scoop out dough and roll into a 1 to 1 1/2 inch ball, depending on your desired sized. Freeze for 15 minutes.
To make the chocolate coating, combine cocao powder, coconut oil and maple syrup (if using) in a small bowl. Stir until no lumps remain. The coating should be thick but not stiff, allow to cool if too thin.
Remove the peanut butter balls from the freezer. Using a skewer or fork pick up a ball and dip into the chocolate leaving a a small round or peanut butter visible at the top. Place back on parchment. Repeat with remaining balls. Place in refrigerator until chocolate sets.
To cover the the hole left by the skewer you can dip your finger in warm water and pinch it closed. Buckeyes should be kept in the refrigerator.
For Paleo, substitute almond butter and vanilla protein powder