Preheat your oven to 160°C (320°F) and line a baking sheet with parchment paper.
Add the oats to the bowl of your food processor and blitz to rough flour consistency.
Next, add the flour, peanut butter, maple syrup (if using) and blitz again.
Add the water 1 tablespoon at a time, blitzing between each addition, until the dough comes together. You may find that you don't need all the water, or that you need a touch more. The dough should be smooth and firm, but not sticky.
On a lightly floured surface, roll out the dough to about 3mm thick.
Use a cookie cutter or knife to cut out shapes for the treats and place on the prepared baking sheet and dock each treat with a fork.
Bake the treats in the preheated oven for 25 to 30 minutes, until lightly golden brown. They may be ever so slightly soft when the first come out of the oven but they will crisp up as they cool.
Once baked, remove the treats from the oven and allow them to cool on the baking sheet for 5 minutes before transferring them to a wire rack. Let them cool completely before allowing your pooch to dig in!
Store the treats in an airtight container or cookie jar at room temperature for about a week, or in the freezer for up to 2 months.