How do I make a crumble with a crisp topping?

A crumble has two problems to solve at once: the topping must stay crisp while the fruit releases steam beneath it. Coarse lumpy topping and fruit that has been thickened rather than left watery solves both.

What you'll need

• Flour
• Cold butter
• Sugar
• Fruit
• Oats or nuts (optional)

Step by step

1. Use roughly 100g butter and 75g sugar to 200g flour.That ratio gives a topping that holds together in lumps without being greasy. More butter gives a richer, more biscuit-like result.
2. Rub cold butter into the flour to coarse lumps.Stop well before fine breadcrumbs. Uneven lumps are what give a crisp, craggy topping rather than a uniform sandy one.
3. Add oats, nuts or demerara for texture.A handful of rolled oats or chopped nuts, or demerara instead of caster sugar, all add crunch that plain topping lacks.
4. Prepare the fruit so it is not swimming.Toss with a tablespoon of cornflour or a little ground almond. It thickens the juices instead of letting them flood the topping.
5. Pre-cook very firm or very wet fruit.Hard apples benefit from a few minutes on the hob; very juicy fruit like rhubarb releases a lot of liquid that is better reduced first.
6. Scatter the topping loosely and do not press it down.Pressing compacts it into a solid layer that steams from underneath. Loose topping lets steam escape and stays crisp.
7. Bake at 180°C for 35-45 minutes until bubbling at the edges.The topping should be golden and the fruit visibly bubbling. Under-baked crumble is pale and doughy.
8. Let it stand for ten minutes before serving.Molten fruit is scalding and the juices thicken slightly as it settles.

Tips

• Crumble topping freezes perfectly. Make a large batch and keep it in a bag — a crumble then takes five minutes to assemble.
• A pinch of salt and a little cinnamon or ground ginger in the topping makes a noticeable difference.
• If the topping browns before the fruit is cooked, cover it loosely with foil and continue.

Common mistakes

• Rubbing the butter in to fine crumbs — It produces a uniform sandy layer that compacts and goes soggy. Coarse lumps stay crisp and craggy.
• Pressing the topping down — It seals the surface, traps steam from the fruit and the underside becomes doughy.
• Using very wet fruit with no thickener — The juices flood the topping from below. A spoonful of cornflour tossed through the fruit prevents it.

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