In a large mixing bowl, combine the rolled oats, protein powder, cocoa powder (if using), and salt.

In a separate bowl, mix the peanut butter and honey (or maple syrup) until smooth.

Add the wet ingredients to the dry ingredients and stir until well combined.

Fold in the chopped nuts, dried fruits, and dark chocolate chips (if using).

Line an 8x8 inch baking pan with parchment paper, leaving some overhang for easy removal.

Press the mixture firmly into the pan, spreading it evenly.

Refrigerate the bars for at least 1-2 hours to set.

Once set, lift the bars out of the pan using the parchment paper and cut into desired sizes.

Store the protein bars in an airtight container in the fridge for up to a week.