Prepare the fruit filling

• Peel, core and slice the apples and rinse the blackberries.
• Toss the fruit with the sugar, cinnamon and water in the baking dish.

Make the crumble topping

• Rub the cold cubed butter into the flour with your fingertips until it resembles breadcrumbs.
• Stir in the light brown sugar and rolled oats.

Assemble the crumble

• Scatter the crumble topping evenly over the fruit filling.

Bake the crumble

• Bake until the topping is golden and the fruit is bubbling.

Serve

• Let the crumble cool slightly and serve warm.