Line an 8×8 pan with parchment paper or a silicone mat.

In a bowl, combine peanut butter, protein powder, maple syrup or honey, and salt.

Stir until a thick dough forms.

Press the dough evenly into the lined pan.

If using melted chocolate, drizzle or spread it over the top.

Refrigerate until firm, about 1–2 hours.

Remove from fridge and cut into 10–16 bars, depending on size.

Store bars in the refrigerator or freezer.