Preheat your oven to 350°F and line an 8x8 baking dish with parchment paper, coating it with non-stick spray.
Peel and dice the green apple, then sauté it with cinnamon and maple syrup until soft and tender.
In a mixing bowl, combine almond butter, maple syrup, coconut sugar, eggs, and vanilla extract until smooth.
Add oats, oat flour, baking powder, cinnamon, and salt, mixing until well combined.
Gently fold in the sautéed apples, then pour the batter into the prepared baking dish and spread it evenly.
Bake for 30-35 minutes, then let the blondies cool completely before adding the glaze.
For the glaze, whisk together powdered sugar, milk, maple syrup, and vanilla extract until smooth. Drizzle over the cooled blondies and let it set for 10 minutes.
Slice into bars and indulge in the deliciousness!