Heat the oven to 190C/170C fan/gas 5. Put the apple, spice and caster sugar in a saucepan with 2 tbsp water. Cover and cook gently for 5 mins until the apples have started to soften, then transfer to an ovenproof dish.

Meanwhile, rub the butter into the flour, then stir in the light muscovado sugar, oats and a pinch of salt. Sprinkle the mixture evenly over the apples.

Put the dish on a baking tray and bake for 35-40 mins until the top is golden and the apples are tender. Leave to cool for 5 mins before serving with cream, ice cream or custard.