Use a paper towel to spread a thin layer of coconut oil on the surface of an 8 x 8.5 glass dish.
Dice apples into roughly 1 inch cubes.
Place diced apples in a bowl.
To the bowl, add the "apple layer" ingredients (diced apples, cinnamon, tapioca flour, and coconut sugar) until well combined.
Place mixed apple layer ingredients into the bottom of the baking dish.
Mix the "crumble topping" layer (vanilla, coconut oil, maple syrup, rolled oats, salt, almond flour, and pecans if using) together in a bowl until well combined.
Place the crumble topping on top of the apple layer in dish. Gently press the topping down so it is evenly distrubuted over the apples.
Bake at 350 for 50-55 minutes until the top is golden brown.
Let cool for at least 15 minutes until slicing. Store for 4-5 days, covered in fridge.