Combine protein powder, collagen, almond flour, salt, monk fruit, and pumpkin pie spice in a food processor.

In a small bowl, stir together the butter, pumpkin puree, and extract.

With the food processor running, stream the pumpkin butter mixture in. Process until the batter comes together in a large ball. Add water a tablespoon at a time and process well to ensure it is incorporated before adding more if it seems too dry. Mix in the chocolate, if using.

I find this mixture to be pretty sticky so I oil my hands or spatula to press it into an 8×8-inch pan lined with parchment or plastic wrap.

Refrigerate until cool and set, about an hour, slice into 12 bars and wrap individually with parchment paper. Store in the refrigerator until eating as they can spoil. These can be taken for travel and will not melt although they will get quite soft and tacky when warm.