Frying basically involves cooking food in hot fat. But it's not quite that simple. You need to take care when frying, because if the fat is too hot, the food will scorch or burn; and if it's too cold, the food will soak up fat and become soggy with grease.
This is an especially important consideration with deep-frying, because when it comes to food such as fish, batter is needed to act as a protective coating, thereby preventing the fish from overcooking.
This week's recipes demonstrate different uses for frying - follow them, and you'll have the finest egg and chips imaginable.
I had to do this recipe eventually, not least because I really believe that these are the best chips in the world. I've spent years looking for the perfect chip, along the way experimenting with just about every possible variable: the oil, the number of cooking processes, the type of potato, temperature, etc. The traditional way to make chips is with two separate cooking processes, not least because if you try to fry the chips in one go, they go brown before the inside has the time to cook. An initial, cooler fry enables the potato to be cooked through, ready for browning in very hot oil later. For me, the perfect chip has a wonderfully crisp exterior and a light, fluffy interior.
We had a problem a while back at the restaurant, in that the meat (a veal kidney) we were serving with chips had to be cooked to a far lower temperature than the chips, so although the meat was at the ideal temperature when served, the chips, being so hot, would make the meat seem cool even when it wasn't. As a result, I set myself the task of coming up with a chip that would keep its crunch for several minutes so that it could be served nearer to the temperature of the meat. I tried many variations, until eventually settling on this recipe.
I also thought long and hard about why chips lost their crunch. Basically, when you cook the chip for the last time, the moisture held in the soft interior turns to steam. This steam wants to evaporate, so penetrates the crisp exterior, and therefore softens it. The solution, then, was to reduce this evaporating moisture, and the easiest way to do this, I thought, was to reduce the moisture levels in the potato. To do this, we tried several things.
Drying the chip in the oven between each cooking process made the chip too dry and almost tough, and it also lost its wonderfully fluffy interior. Pinpricking the chip as soon as it comes out of the water in the first cooking, allowing steam to escape more easily, worked pretty well, but the thought of stabbing each chip nearly 25 times was a little impractical, to say the least.
I then discovered a desiccator. This is a container with a valve on the side that can be fitted to a pump. When the pump is on, it sucks air and, with it, excess moisture from whatever is inside it, particularly when the food is put in it while still warm. Placing the chips in this vessel in between each of the cooking processes drew out just the right amount of moisture to prevent excess steam from building up during the final cooking process. The only downside is that, as the chip cools during the second of the three cooking processes (the first time that it is cooked in fat), some of the fat left on the chip when it is removed from the oil is absorbed. As the chip cools, the outward pressure caused by the steam inside the chip dies down - because it is this pressure that prevents the fat from being absorbed in the first place, the cooling chip absorbs the fat.
I did try cooking the chip by placing it in warm oil and gradually increasing the temperature so that the potato gradually cooked and browned at the same time. Although this meant that the chip absorbed little fat, it did not come out as crisp. The following recipe by no means leaves the chips fatty - but, to my mind, if you are at all worried about any of this, cook something else instead.
The only other thing to say about cooking chips is that the potato you use makes a huge difference. For me, nothing can beat the Golden Wonder potato, but it is pretty difficult to obtain; Maris Piper and King Edwards work well, too.
There is no need to give quantities for this recipe, not least as I'd hate to be blamed for short-changing you on the number of fabulous chips you will end up with. Just make sure that you have your fryer filled to the correct level.
Brand new oil is not always the best to use. If you do decide to make chips on a regular basis - and, believe me, having tried these, you will - save a little of the old oil in the fryer to add to new oil. This helps prevent the chips from scorching.
So, let's make chips. Wash, peel and cut the potatoes into chip lengths. Don't worry if they're a little uneven, because this means that you'll get a range of textures, from thicker, luxuriant, fluffier chips to more crisp-edged pieces.
Place the cut chips in a bowl of cold water and, when you have finished cutting them all, leave the bowl under the cold tap for five minutes to remove excess starch. Bring a large pan of unsalted water to a simmer and drop in the chips. Cook until the potatoes are soft, ideally to that point just before they start falling apart. With a slotted spoon, carefully lift out the chips and place on a tray, board or, best of all, a cake rack, then leave to cool. Once cool, place in the fridge for at least half an hour.
Preheat the fryer to 130C. Cook the cold chips at this level until they take on a dry appearance on their surface - you don't want them to colour at all. Drain, and leave to cool again. When cool, refrigerate again for at least half an hour.
Increase the temperature of the oil in the fryer to 190C. Plunge the cold chips in this and cook until golden brown and crisp. Drain, salt and serve at once.
This simple but clever way of obtaining a perfectly cooked yolk and white comes from Bernard Loiseau, whose eponymous restaurant in Burgundy has three Michelin stars. Ideally, you need a stainless-steel egg ring and a small, non-stick frying pan. The egg ring is not essential - it just helps to hold the shape of the white.
I should also mention that it is vital to use only the freshest of eggs, because their whites will remain compact and not run everywhere.
1 best-quality free-range egg
1 knob butter
Salt and pepper
A few drops balsamic vinegar
Pre-heat the oven to 245C/475F/gas mark 9. Break the egg and carefully separate the white from the yolk, making sure to keep the yolk whole. Put the knob of butter and a soupspoon of water into the frying pan and heat until foaming (the water helps to stop the butter from getting too hot, which is why the whites brown and toughen). Salt and pepper the pan so that the underside of the white gets seasoned, too. When the butter begins to foam, carefully slide in the white.
Put in the oven and cook for a minute and a half. The top should still be trembling. Now season on top - seasoning the white like this means you won't tarnish the yolk's wonderful golden colour by speckling it with pepper. Put the raw yolk in the centre of the white, and return to the oven for two minutes. Dot with a few drops of balsamic vinegar, and serve.
Of course, if this seems like too much hassle, simply fry your eggs as you would normally, only please remember the following: use the best-quality butter or oil possible; do not have the pan too hot or cold - too hot, and the white will be overdone before the rest has had time to cook, too cold, and the white will begin to run; cover the pan to obtain a more even cooking, but be careful as the egg will also cook quicker; only ever salt the egg at the last minute before cooking
· Heston Blumenthal is chef/proprietor at The Fat Duck, Bray, Berkshire (www.thefatduck.com).