Combine peanut butter, protein powder, maple syrup, and salt in a mixing bowl to make a dough.
Line an 8x8 pan with parchment paper (or aluminum foil).
Smooth the dough into the lined pan.
If not including the chocolate topping, cut into bars and then place in the freezer.
If including the chocolate, spread the melted chocolate over the dough and then chill in the freezer.
When chilled to liking, enjoy!
Place bars in a freezer bag once sufficiently chilled to store long-term.