Start by lining a muffin tin with cupcake liners or silicone molds for easy removal.

In a microwave-safe bowl, combine the dark chocolate chips and melt them in the microwave in 30-second intervals, stirring between each until smooth. Alternatively, use a double boiler on the stove.

Spoon a small amount of melted chocolate into the bottom of each muffin liner, just enough to cover the base. Use a spoon to spread it evenly. Place the muffin tin in the freezer for about 10 minutes until the chocolate hardens.

In a mixing bowl, combine the natural peanut butter, protein powder, maple syrup (if using), and a pinch of salt. Mix until fully combined and creamy.

Once the chocolate layer is hardened, spoon some of the peanut butter mixture into each cup, filling it to the top but leaving space for the final chocolate layer.

Pour the remaining melted chocolate over the peanut butter filling in each cup, smoothing it out with a spoon.

Place the muffin tin back in the freezer for another 20-30 minutes to set completely.

Once set, remove them from the freezer, peel off the liners, and enjoy your homemade Protein Peanut Butter Cups!