Lightly oil 4 x 300 ml (½ pint) individual baking dishes or cups with spray oil. Peel, core and thickly slice the apples and put in a saucepan with the butter, sugar, cloves, sultanas and measurement water. Cover and cook over a low heat for 5–6 minutes until the apples are just softened. Divide between the prepared dishes or cups.
Put the oats, flour, ground hazelnuts, sugar and cinnamon in a bowl and stir well until combined. Add the butter and rub in with the fingertips until the mixture resembles coarse breadcrumbs. Spoon the crumble topping over the apple mixture and bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 25 minutes until bubbling and golden.