Preheat the oven to 350°F and line a baking sheet with parchment paper.

In a medium bowl, whisk together the oat flour and chopped parsley.

In a separate bowl, whisk the mashed sweet potato, egg, and water until smooth.

Add the wet mixture to the dry ingredients and stir until a soft dough forms.

Lightly flour a work surface with a little oat flour and roll the dough to 1/4-inch thickness.

Use small star-shaped cookie cutters (or any small cutter) to cut out treats and place them on the prepared baking sheet.

Gather and reroll the dough scraps until all the dough is used.

Bake for 18–20 minutes, or until the treats are firm and the edges are just turning light golden.

Remove the treats from the oven and let them cool completely on a wire rack before serving to your dog.