Preheat the oven to 400°F and grease a 12-cup muffin tin.

Make the crumble topping: In a medium bowl, whisk together the flour, brown sugar, and cinnamon. Add the coconut oil and use a spatula to combine. Mix just until there is no dry flour remaining and the mixture is crumbly. Don’t overmix.

Make the muffins: In a large bowl, whisk together the all-purpose, whole wheat, and almond flours, baking powder, apple pie spice, and salt.

In a medium bowl, vigorously whisk together the almond milk, applesauce, sugar, avocado oil, eggs, and vanilla.

Pour the wet ingredients into the dry ingredients and stir to combine. Gently fold in the apple. Use a 1/3-cup measuring cup to scoop the batter into the prepared muffin cups. Sprinkle the crumble topping on top. Bake for 17 to 22 minutes, or until a toothpick inserted comes out clean. Let cool for 10 minutes, then transfer to a wire rack to cool completely.

Make the glaze: In a small bowl, whisk together the powdered sugar and 1 tablespoon almond milk until smooth. If the glaze is too thick, add more almond milk, 1 teaspoon at a time, until it reaches a drizzleable consistency. Drizzle over the cooled muffins.