Preheat the oven to 350F. Line a baking sheet with parchment paper or a silicone baking mat and set aside. Pat your blueberries dry with a clean kitchen towel of paper towels if you have just washed them.

Add the applesauce, maple syrup, almond butter, and vanilla (if using) to a large mixing bowl. Use a whisk to mix well, until the almond butter and applesauce are evenly combined.

Add the oat flour, almond flour, ground flax, baking powder, cinnamon (if using), and salt to the bowl and mix well, until a thick batter forms. Add the rolled oats and blueberries and use the spatula to gently fold them into the batter, until combined.

Use either a ⅓ cup cookie scoop or ⅓ measuring cup and spatula to scoop a heaping ⅓ cup “cookie” out of the batter, then place it on the prepared baking sheet without flattening it. Repeat with the remaining batter; you should have 8 medium cookies.

Bake in the middle rack of the oven for 22 to 25 minutes, until the cookies have spread and the outer edges of the cookies are just slightly brown.

Remove from the oven and let the cookies rest on the baking sheet for 20 minutes, to firm up. Then, use a firm spatula to transfer them to a wire rack and let cool completely.

Serve immediately, or store any leftovers in an airtight container in the refrigerator for up to 5 days, or freeze for up to 2 months and thaw when the craving strikes.