A crumble can be cooked up to 24 hours ahead of serving. Store in the fridge and reheat in a preheated oven, 180°C/350°F/gas mark 4, until heated through and bubbling.
Crumble topping can also be frozen for up to 2 months.
Oaty crumble topping
Rub 70g/3 oz cold butter, cut into cubes, into 100g/3½ oz plain flour/all purpose flour until it resembles breadcrumbs. Stir in 50g/2 oz caster sugar/fine white sugar and 50g/2 oz porridge oats. This will serve 6.
Caster sugar can be replaced with brown sugar.
Sprinkle muesli over the top of fruit before cooking.