Steps
1. Preheat the oven to 350 degrees F (175 degrees C).
2. Place the apples in an ovenproof dish and sprinkle over the caster sugar.
3. Cut the butter into small cubes and rub it into the flour, oats, light brown sugar, cinnamon, and nutmeg until it resembles rough breadcrumbs.
4. Scatter the crumble topping over the apples and bake for 25-30 minutes until the apples are tender and the topping is golden brown and crisp.
5. Serve warm with natural yoghurt.