Preheat the oven:
Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone baking mat.

Mix the dry ingredients:
In a medium-sized bowl, combine the rolled oats, whole wheat flour (or oat flour), and cinnamon (if using). Stir to combine.

Combine the wet ingredients:
In a separate bowl, whisk together the egg, applesauce, peanut butter, and shredded carrot. Add the finely chopped apple to this mixture and stir until evenly combined.

Combine wet and dry ingredients:
Gradually add the wet mixture into the dry ingredients, stirring until a dough forms. If the dough feels too sticky, add a little more flour or oats to achieve a firm, workable dough.

Roll out the dough:
Lightly flour your surface or use parchment paper to roll out the dough to about ¼-inch thickness. Use a cookie cutter or simply cut into small squares or rectangles, depending on your dog’s size and preference.

Bake the cookies:
Place the cookies onto the prepared baking sheet, spacing them about 1 inch apart. Bake in the preheated oven for about 20-25 minutes or until the cookies are golden brown and crisp.

Cool:
Once baked, remove the cookies from the oven and let them cool completely on a wire rack.

Serve:
Serve these crunchy cookies to your dog as a treat. Store any leftovers in an airtight container at room temperature for up to 1 week, or freeze for longer storage.