Preheat Oven: Set oven to 350°F (175°C) and lightly grease a 9x13-inch dish.
Prepare Apples: Peel, core, and slice apples into ¼-inch thick pieces.
Make Filling: In a large bowl, mix apples with sugar, flour, lemon juice, cinnamon, nutmeg, and salt. Spread in the baking dish.
Make Topping: In another bowl, combine oats, flour, brown sugar, cinnamon, and salt.
Add cold butter and mix until crumbly. Stir in nuts if desired.
Assemble u0026 Bake: Sprinkle topping evenly over apples. Bake for 40–45 minutes, until golden and bubbly.
Cool u0026 Serve: Let cool 15 minutes before serving. Enjoy warm with ice cream or yogurt.
