1. Peel, core and slice 5 large green apples. Place in a bowl with 10g caster sugar, ½ tsp ground cinnamon and 2 tbsp lemon juice.
  2. Mix to combine and transfer to a baking dish.
  3. Prepare the crumble ingredients: 225g plain flour, 90g oats, 1 tsp ground cinnamon, 165g caster sugar and 225g cold, cubed butter.
  4. Combine the flour, oats, cinnamon and sugar in a mixing bowl. Rub in the butter until it is crumbly.
  5. Scatter the crumble topping over the apples and bake at 180˚C/160˚C fan/gas mark 4 for 35-40 minutes or until the crumble is golden and the apples are soft.
  6. Serve with vanilla ice cream.