Ground oats replace flour in this easy delicious dessert. Use gluten-free oats to make it suitable for those with celiac.
Topping: Preheat oven to 375 degrees. Pulse 1/2 cup oats in a food processor until coarsely ground. Transfer to a bowl and add remaining 1/2 cup oats, brown sugar, salt, and butter. Stir until combined.
Filling: Toss together filling ingredients in a bowl and transfer to a 9-inch-square baking dish. Sprinkle with topping. Cover with parchment-lined foil and bake 30 minutes. Remove foil and continue baking until apples are tender and topping is golden brown, about 30 minutes more. Let cool slightly before serving.