1) In a heavy based saucepan mix the apples butter and sugar with a splash of water.
2) Cook down for around 30 minutes, stirring regularly until the apples form a purée.
3) Taste the mixture, if it is too tart add a little sugar and if it is too sweet add a little lemon juice.
4) leave the purée to cool and then stir in the blackberries.
5) Pour into an oven proof dish. Make sure it is big enough to hold the crumble topping.
6) Rub the flour together with the cold butter, until it resembles breadcrumbs.
7) Add the sugar and turn out into a baking tray.
8) Bake in a pre heated oven at 180°C for 8-10 minutes. Cooking the crumble first gives you a crunchier topping with no claggy undercooked crumble.
9) Scatter the topping over the fruit base and bake at 180°C for 10-12 minutes.
10) Enhance your favourite custard with a little Denholme Gate honey.
Chef's Top Tip
Fancy leftover crumble for breakfast? Layer the cold fruit purée with Hesper Farm Skyr vanilla yoghurt in a large wine glass and top with the crumble mix.