Dice apples and stir in the sugar, cornstarch, cinnamon, and lemon juice.
Add the brown sugar, gluten-free oats, melted coconut oil, almond flour, cornstarch, and salt. Mix to fully combine.
Add the apple mixture to a baking dish, then add the crumble topping to the baking dish.
Bake for 35-40 minutes or until the crumble turns golden brown. Optional: Serve with a scoop of your favorite vegan vanilla ice cream.