In a medium mixing bowl, combine the pumpkin, eggs, and peanut butter, and stir well.
Add 2.5 cups of flour, and stir to combine. The dough should be about the consistency of play-dough: soft and easy to roll out, but not wet and sticky. Add more flour as needed to reach this consistency.
Divide the dough into 2 pieces. Working with one piece at a time, roll it out on a well-floured surface until it is 1/2-inch thick.
Cut the dog treats out using a cookie cutter, or you can simply cut them into squares using a knife.
Place the cut-out cookies on a parchment-lined baking sheet.
Repeat with remaining dough, gathering and re-rolling the scrap dough until all the dough is used.
Bake for 20 minutes or until cooked through.
Store in an airtight container in the fridge for up to a week or in the freezer for 3 months.
Notes
The homemade dog treats will still be a little soft at the 20 minutes mark. My pup prefers them like this. Their shelf life is shorter like this, though (this is why you keep them in the fridge or freezer).
Bake for an additional 10 minutes if you'd like a crisp dog treat. They are more shelf stable when they are cooked longer, but the fridge or freezer will still prolong their usability.
Let treats thaw at room temp for a few minutes before giving to you dog.
Make sure your peanut butter doesn't contain artificial sweeteners like xylitol—it's toxic for dogs.