Preheat oven to 350°F.
In a bowl, mix diced apples with sugar, 2 tbsp butter, cinnamon, and nutmeg. Divide among 4 ramekins or a baking dish.
In another bowl, combine oats, brown sugar, flour, softened butter, and salt until crumbly.
Sprinkle the crumble mixture over the apples.
Bake for 20-25 minutes until the topping is golden and apples are tender.
Let cool for 5 minutes before serving. Serve warm, optionally with vanilla ice cream.