Add the pumpkin seeds, oats, and hemp hearts to a food processor. Blend until coarse and mealy.
Add the pitted medjool dates and blend until broken down into small pieces.
Add the collagen peptides and peanut butter. Blend until fully combined.
Drizzle in 2 tablespoons of water and blend again. Add more water as needed until the mixture starts to clump together.
Transfer the mixture to parchment paper and press into a rectangle about 4.25 x 10 inches.
Melt the dark chocolate in a heatproof bowl set over a small pot of simmering water. Stir until smooth.
Spread the melted chocolate evenly over the bars. Add optional toppings if using.
Chill in the refrigerator for 30 minutes, or until set.
Slice into 8 bars with a sharp knife.