Start by heating your oven to 350°F (175°C). Prepare a baking sheet by lining it with parchment paper or a silicone baking mat.
In a large mixing bowl, mash the blueberries using a fork or potato masher until they’re broken down but still have some texture.
Add the egg, peanut butter, applesauce, and coconut oil to the mashed blueberries. Stir everything together until well blended.
Next, mix in the rolled oats, and flour. Stir until a dough forms. If the dough feels too sticky, add a bit more flour; if it seems too dry, mix in a little water.
Lightly flour your work surface and roll out the dough to about ¼ inch thick. Cut out shapes using a cookie cutter and place them on your lined baking sheet.
Bake for 20 to 25 minutes, until the treats are golden and slightly firm to the touch. Allow them to cool completely before giving one to your pup.