Prepare oat topping by adding oat flour, coconut oil, maple syrup, nutmeg, cinnamon, and oats to a large bowl. Using a fork, slowly mix the ingredients together until fully combined and large crumbs form. Set aside.
Add sliced apples to a 7x11 or 9x9 baking dish.
Top the apples with prepared the oat topping.
Bake in the preheated oven for about 35 - 40 minutes, until the top is golden brown and the apples are fully cooked and soft.