Blackberry crumble Picture: The Independent
Apple and blackberry crumble with a macadamia nut and vanilla topping by Chef Adam Gray

Apple crumble topping:

250g plain flour
170g butter
110g macadamia nuts
110g almonds, nibbed
110g demerara sugar
4 drops vanilla extract
Salt

Apple crumble filling: 

4 granny smith apples
50g butter
200g blackberries
50g sugar

To plate: 

1 dollop custard

To make the apple crumble topping, preheat the oven to 160C. Combine all the ingredients in a food processor and blend until the mixture is the texture of breadcrumbs​. Spread out the crumble on a baking tray and put it in the oven for 30-40 minutes, being sure to stir the crumble mixture every 10 minutes. Remove when the mixture is golden brown and set aside to cool.
To make the apple filling, peel and core the apples then cut them into even-sized pieces about 3-4cm wide. Put a heavy-based saucepan over a medium heat and add the butter. When it starts to foam, add the apple pieces.

Cook gently for 5-8 minutes until the apple is just becoming tender, then add the blackberries and sugar and continue cooking for a further 8-10 minutes. Spoon the filling into an ovenproof dish and sprinkle liberally with the crumble topping. Bake for 10-12 minutes before serving with hot custard, cream, vanilla ice-cream or all three.