Toss sliced apples with lemon juice, brown sugar, cinnamon, nutmeg, and flour.
Spread mixture in a greased baking dish.
In a bowl, combine oats, flour, and brown sugar. 5. Cut in cold butter with a pastry cutter or fingers until crumbly.
Sprinkle topping evenly over apples. 7. Bake 35–40 minutes, until apples are bubbling and topping is golden. 8. Serve warm with ice cream, whipped cream, or a drizzle of cream.