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

Add the flour and cinnamon (if using) to a medium bowl and whisk to combine and remove lumps.

In a separate bowl, stir together the pumpkin puree and peanut butter until smooth.

Add the water or low-sodium broth to the pumpkin mixture and stir until fully combined.

Pour the wet mixture into the bowl with the flour and stir with a sturdy spoon until a dough begins to form.

Use your hands to gently knead the dough in the bowl or on a lightly floured surface until it is smooth and slightly tacky but not sticky; add a teaspoon of water if too dry or a sprinkle of flour if too sticky.

Place the dough on a lightly floured surface and roll it out to about 1/8 inch thickness.

Cut the dough into small wafers using a knife, pizza cutter, or small cookie cutters and transfer them to the prepared baking sheet, spacing them slightly apart.

Bake for 20 to 25 minutes, or until the wafers are dry and lightly golden around the edges.

Turn off the oven, crack the door open, and let the wafers sit inside for an additional 10 minutes to dry and become crunchier.

Transfer the wafers to a wire rack and let them cool completely before serving to your dog.