Peel, core and chop the apples, then put them into a pan with the butter and a tablespoon water cook together for 5 minutes until beginning to soften, add the Tate & Lyle Demerara Sugar then remove from the heat. Gently fold in the blackberries and tip into an ovenproof dish or four individual dishes or cups.
To make the crumble, put the flours into a bowl with the cinnamon, dice the butter and add to the bowl, then rub together until the mixture looks like rough crumbs. Stir in the Tate & Lyle Demerara Sugar and nuts. Scatter over the fruit and bake for 20-25 minutes until the topping is crisp and golden.
Serve with thick cream or crème fraiche.
Chef's Tip
If you're baking the crumble for someone with a nut allergy, simply replace the hazelnuts with a small handful of oats.