In a large bowl, toss all of the filling ingredients together. Make sure the apples are evenly coated. Spoon into a 9-inch pie dish, cake pan, or square baking pan. Set aside.
For the topping, whisk the brown sugar, oats, and almond meal together. Make sure there aren't any huge chunks of brown sugar. Then, whisk in the cinnamon and salt. Once all combined, stir in the melted butter until combined. Sprinkle topping over the apples and finish with a few slivered or sliced almonds-- these extra almonds on top are optional.
Bake for 30-35 minutes or until the filing is bubbly, the apples are a little soft, and the topping is browned. If it looks like the topping is browning too quickly, cover the top loosely with aluminum foil. Allow to cool for 10 minutes.