Preheat oven to 350.
Line an 8 inch round pan with parchment paper (grease inside so it sticks).
In a small bowl, whisk together the milk and acv, and set aside, giving it time to curdle.
In another small bowl, make flax eggs (whisk flax and water) and set aside.
Next, in a medium bowl, whisk together the almond flour, oats, tapioca, coconut sugar, baking powder, baking soda, cinnamon, and salt, and get clumps out.
Add melted coconut oil and flax eggs to the curdled milk, whisking until smooth.
Then pour it into the dry ingredients, coating everything well.
Fold in chocolate chips.
Transfer batter to the pan, using a spatula to even out.
Finally, make crumble.
In a medium bowl, stir almond flour with coconut flour, oats, salt and coconut oil, followed by maple syrup.
Once dry ingredients are moistened, add chocolate chips and scatter evenly over the batter.
Bake 45-55 minutes.
Cover halfway with foil to avoid too much browning.
Let cool completely before cutting into 10 slices.