Preheat oven to 350F. Line a baking sheet with parchment paper.
In a large mixing bowl, whisk together pumpkin puree, peanut butter, egg, and cinnamon until smooth. Slowly beat in flour and water, alternating between each, until everything is combined.
Turn the dough out onto a well floured surface and roll to about ¼-inch thick. Cut with desired cookie cutters and transfer to the prepared baking sheet.
Bake for 20 minutes. Cool completely before treating your pup!