2granny smith or other tart dessert apples - peeledcored, and thickly sliced
25ggolden caster sugar
Preheat the oven to 190℃/180℃ fan/gas mark 5.To make the crumble melt 50g of the butter in a frying pan and stir in the oats. Cook gently over a low heat stirring until pale golden. Remove from the heat and allow to cool slightly.
Rub the remaining butter into the flour until the mixture resembles coarse breadcrumbs. Add the caster sugar, chopped nuts, and the oats and stir until well combined. Set aside.
Place both types of apple slices in an ovenproof dish.
Lightly crush the fennel seeds in a pestle and mortar, or between two large spoons and sprinkle over the apple slices. Sprinkle over the caster sugar. Toss in the dish to combine and level as best as you.
Spread the crumble mixture over the fruit and sprinkle with the demerara sugar. Bake for 40–50 minutes until the crumble is golden.
The crumble mixture can be made in advance and stored in the refrigerator for up to 1 week or in the freezer for up to 3 months. Freeze: Make individual portions and freeze after baking.