Preheat the oven to 170°c fan
Peel and core the apples. Cut them in half, then cut each half in half again and then cut each of those pieces in half again. See pictures below.
Put the apple pieces into an oven proof baking dish. Add 1 1/2 tbsp caster sugar to the apples and mix well. Then set aside.
In a mixing bowl add 175g plain flour and 110g caster sugar. Mix together. Then get 110g of butter straight from the fridge and cut into small chunks. Add to the bowl.
Using your fingertips rub the butter into the flour and sugar until the mixture resembles fine breadcrumbs and there are no chunks of butter left. Be patient becuase this will take a few minutes but it makes all the difference to the topping.
Put the crumble topping over the apples. Then using a fork evenly spread the topping and press it down firmly all over. Using a fork gives the crumble more texture.
Put into the oven for 35-40 minutes until golden brown.
