To a food processor, combine the nut butter, maple, protein powder, oat flour, flax seed and dates. Puree until smooth.
Fold in the "add ins" of your choice.
Line a 6" square pan with parchment paper with "wings" coming out of both sides. Press the ingredients firmly into the pan. Top with your favourite add-ins and freeze for 10 minutes. Cut into bars. They will thaw pretty quickly so I recommend enjoying them out of the freezer.