In a bowl, mix together the peanut butter, protein powder (if using), maple syrup, coconut, and chocolate chips until well combined.
Using a mini muffin tray, scoop a tablespoon sized amount of mixture into each muffin hole. Press down firmly so the base is even. Repeat until all the mixture is used.
In a heatproof bowl, melt the chocolate chips and coconut oil together (microwave in 30-second bursts).
Spoon the melted chocolate over each peanut butter base until the tops are covered.
Place the tray in the freezer to set for 1-2 hours. Once firm, remove the peanut butter cups from the tray and store them in an airtight container in the fridge.
