How to make the perfect crumble

I've always been greedily interested in food. When I was 5, I decided I was going to be the chef of my own restaurant — located underwater, naturally. I can still remember the menu I laboriously drew up: vegetable soup, roast chicken, apple crumble. Admirably balanced, I'd say, if perhaps a little light on seafood for the setting — and although I might go for something more adventurous on the savoury side today, I'd still pick a crumble over any number of chocolate fantasias or Pernod panna cottas for afters.

It's the classic childhood pudding; hot, sweet and incredibly comforting. The sad thing is that I've never managed to make a crumble that matched up to the stuff we were served at school. Dot the dinner lady, I salute you.

Crushed amaretti biscuits and cardamom seeds are all very well if you like that kind of thing, but they weren't in our school kitchen, so I seek out advice from less showy sources. I'm surprised to discover, from Mary Norwak's excellent English Puddings, that the first printed mention of the dish is in the 1950 edition of Fanny Farmer's Boston Cookbook. The Oxford Companion to Food suggests crumble probably originated during the Second World War, as a quicker, easier alternative to pastry.

Basics

In homage to these humble origins, I decide to start off with the plainest crumble recipe I can find, in Nigel Slater's Real Fast Puddings. It contains just four ingredients: fruit, flour, sugar and butter. I briefly whizz 175g plain flour in the food processor with 175g butter until it resembles coarse breadcrumbs and then stir in 100g caster sugar and sprinkle over a little water, so it comes together. This goes on top of stewed apples and blackberries and into the oven at 200°C for 30 minutes until golden and crisp, by which time the juices of the fruit have bubbled through the topping and caramelised promisingly on the surface. The result is good and without too much sponginess either.

Water?

I've never heard of adding water to a crumble topping before, although now that I know the history of the dish, it makes sense in a frugal sort of way and it certainly seems to have done the trick when it comes to binding the thing together. The resulting crumble is a bit less craggy and interesting — it tastes the same.

Freezing?

Nigella Lawson's a woman who looks like she knows how to appreciate a good crumble — and her method in How to Eat intrigues me. She claims the texture of the topping is improved by giving the mixture a "quick blast in the deep-freeze" after it's been rubbed together.

I give her recipe a whirl: 120g flour, 90g butter and 6 tbs sugar, rubbed together into a mixture that resembles "porridge oats". Half goes into the freezer for ten minutes and the remainder goes into the oven immediately, on top of another bowl of stewed apple and blackberries. When they're both ready, I look carefully. There's not much in it but the chilled mixture is indeed studded with a few more lumps and bumps than the one cooked straightaway, which suggests that freezing is a good tip.

There's the rub

Lawson also claims that rubbing the butter in by hand makes for a "more gratifyingly nubbly crumble", although I don't find the mixing as "peculiarly relaxing" as she does. I'm not averse to going back to basics if it means saving on washing up, so I make another half batch of her recipe and rub in the butter to the flour and sugar with my fingers. I can't tell the difference once cooked — but I would second her caution to go carefully if you're using a food processor and pulse it rather than switch it on full.

Sugar

Norwak has stern views on crumble, which she condemns, in its English incarnation, as "dull and insipid". We should take a leaf out of the American book, she says, by using fresh, rather than stewed fruit and a crisp butter, brown sugar and spice topping.

As I've moved on to Victoria plums, I leave out the 6 tbs water and 75g sugar in her recipe but I do top the halved fruit with her crumble mixture of 50g butter, 25g light, soft brown sugar and 75g plain flour. I omit the pinch of ground ginger too. I like the flavour of the soft brown sugar but the fine texture makes the finished crumble topping a little sandy. Granulated demerara sugar would add crunch and flavour but also graininess. So I settle on a half and half demerara and golden caster sugar mix as a compromise.

Go nuts

Slater suggests almonds go best with stone fruits. I find her recipe slightly spongy, though and which, although delicious, lacks some of the craggy crunch. Reducing the ratio, as Slater suggests, to a quarter or a third of the flour weight would help lighten things up again while retaining that sweet, nutty quality. Rolled oats are also a nice addition to an apple crumble but I like a handful scattered on top, rather than mixed in, so they toast, rather than cook into a stodgy porridge below. Spices — ground cinnamon, ginger and so on — also work well in moderation. In fact, you can play around with flavourings, if you must, as much as you like, as long as you keep the mixture fairly light and not overwork it. Crumble should be quick, simple — and served with thick custard.