Zest is the outermost part of the rind of oranges, lemons, limes and other citrus fruit. This part of the rind is full of tiny capsules containing a very highly flavored volatile oil, and it is this oil that gives an intense flavor to many savory dishes, sauces, cakes, desserts and preserves.

For the purest flavor, the zest must be removed from the fruit without even the smallest trace of the bitter white pith underneath it. The easiest way to do this is to use a zester or a stainless-steel potato peeler, or you can rub it carefully against the finest cutter on a grater.

Fruit that has been waxed should be washed first, very gently with a soft brush and in warm, not hot, water. Scrubbing the fruit hard can damage the skin which will then release the oil, and it will be washed away with the water.

The skin of young zucchini is thin and need not be removed for most purposes, but the dark green skin of older zucchini can be bitter and should be removed. One garnishing treatment calls for just some of the skin to be discarded: using a potato peeler, shave the vegetable thinly lengthways to produce very thin slices. Throw away the first slice and the last, which consist mostly of green skin, and drop the remaining, green-edged slices into a pan of boiling water. Drain and refresh them under the cold tap as soon as the water returns to the boil.

Yes, yogurt can be used instead of fresh cream in many dessert recipes, such as cheesecakes, ice cream, mousses and cold souffles. The flavor of the finished dessert will be sharper when made with yogurt rather than cream, but it will be just as satisfying.

Yogurt is also an excellent substitute for sour cream in savory dips, marinades and salad dressings. And in the Middle East it is strained overnight through a sieve lined with muslin to produce a soft yogurt cheese, called labne. This is served plain, or flavored with herbs such as thyme.

There are many types of yogurt available, ranging from those with a very low fat content to creamy and thick Greek-style yogurts, which can contain up to 7.5 percent butterfat. But even the thickest yogurt contains less fat and kilojoules than fresh cream, so it makes for healthier dishes.

Full-fat yogurts generally freeze better than lower-fat ones, although they will separate when thawed. All yogurt should be defrosted slowly and given a good whisk before being used. Plain yogurt can be kept frozen for up to two months. Yogurt with added fruit, honey or flavoring freezes slightly better than the plain variety, and can be kept frozen for up to three months in the sealed carton it came in. Homemade flavored yogurt should be frozen in sturdy plastic containers with tightly fitting lids.

Bio or BA yogurt is made with different live cultures, called bifidus and acidophilus. It is often claimed that these particular bacteria aid digestion by supplementing the body's natural flora. When these bacteria are used as the starter for your own yogurt they will reproduce and make bio yogurt. Bio yogurt is not as sharp as ordinary yogurt, and has a milder, creamier flavor. All yogurts are easier to digest than plain milk, because of the action of the bacteria, and they are a good source of calcium and phosphorus, which are essential for strong teeth and bones. Yogurt is also said to be good for maintaining the general health of the skin and the digestive system, and yogurts that have soluble fiber added to them may help to lower the level of cholesterol in the blood.

With the exception of long-life yogurt, all yogurts contain active but friendly bacteria and are therefore 'live'. Yogurt is a cultured product, produced by fermenting milk with bacteria. Several kinds of bacteria can be used, but two of the most common are Lactobacillus bulgaricus and Streptococcus thermophilus.

To make yogurt, the milk is first heated to destroy any unwanted micro-organisms, then a yogurt starter containing the chosen bacteria is added to set and sour the milk. This produces a refreshing, slightly acidic flavor. The bacteria remain active even while the yogurt is refrigerated, so the level of acidity gradually increases. This limits the storage life of yogurt, which will eventually come to taste unpleasantly tart.

The wok is an extremely versatile cooking utensil. It can be sued for braising, boiling and steaming as well as for stir-frying. With a domed lid, it can be used to braise a whole chicken, duck, or a large joint of meat.

The wok is also especially effective for steaming. Put a pair of bamboo chopsticks across the bottom of the wok. Put the food in a deep plate and rest the plate on top of the chopsticks. Add water up to a level just above the chopsticks. Cover with a lid that fits over the wok without pressing down on the food to allow the steam to circulate and cook the food gently.

** Chinese Cooking **

Yes, very easily. The basic sauce for stir-frying is simply a blend of seasonings: salt or soy sauce, pepper and a little sesame oil. You can also add oyster sauce, sherry, Chinese wine or any of the Chinese bottled sauces such as black or yellow bean, and a selection of fresh flavoring ingredients such as galangal, ginger, lemon grass and fish sauce. Soy and fish sauces are used in Asian cooking instead of salt so if you use them, do not add any extra salt.

** Asian Cooking **

Yes, what is most important is the stirring action: you should use your wrist to scoop, flip and push the food continuously. A wok ladle has a curved end that is designed to get right to the bottom of the wok so that it is easy to flip the food over when stir-frying. Whether you use a wok ladle or a wooden spatula, every bit of food in the wok must be moved about constantly, over the entire surface of the wok. Most foods need no more than 5 minutes cooking, less with intense heat.

** Asian Recipes **

Wholemeal breads and pastries are made using 100 percent wholemeal wheat flour, which is milled from the whole grain including the outer husks. This means that it contains more nutrients than the processed, dehusked white flours, but it also means that wholemeal flour needs to absorb more liquid than white flour to soften the ground husk. This often results in doughs or pastries that are heavier, though they are wholesome and nutritious with good flavor. To avoid this heaviness, your recipe needs to be adjusted accordingly.

Wholemeal pastry is best used as a base for flan cases rather than a top crust, for it does not have the light, short or flaky texture of white flour pastry. To compensate for this, roll wholemeal pastry thinner than pastry made with white flour, and always prebake or bake blind if making a base or pastry case.

For lighter breads and pastries you can use half wholemeal and half white flour. This results in a less heavy-textured bread, which has added crunch from wheat berries, which are whole husked grains of wheat also called wheat kernels.

Wheatgerm is the heart of a grain of wheat with all the nutrients of the grain intact. It is available natural or toasted, which gives it an even nuttier flavor. Its main use in the kitchen is as a breakfast cereal, adding a crunchy bite to muesli or sprinkled over fresh fruit and yogurt. It can also be mixed into crumble toppings, or sprinkled over bread dough.

Yes, but only briefly. Watercress is often wilted into hot sauces and soups, to which it adds its lively green bite. Wilting occurs in an instant when watercress comes into contact with hot liquid. It does not need any more cooking than this. Watercress is especially useful for combining with spinach or in potato-thickened soups, which are equally good served hot or chilled. Chopped watercress stirred into hot butter and seasoned with salt, pepper and lemon juice makes a simple sauce for fish and looks equally beautiful with the white flesh of sea fish or the coral pink of salmon and trout.

The sharpness of chopped watercress is also very welcome when stirred into purees of winter root vegetables, particularly swede. And it is excellent in souffles, such as those flavored with cheese.

** Easy Recipes **

It is. With 2.2 mg of iron per 100 g, raw watercress certainly makes it into the top league of healthy iron-rich vegetables. Only raw parsley, mint and lentils have more iron, and spinach has less. Watercress is only really at its best when the leaves are absolutely fresh and vivid dark green so avoid any with traces of yellowing. To keep watercress fresh, store it with the leaves submerged in a bowl of cold-water - easier if you buy it in a bunch, not loose.

** Asian Recipes **

Since plant foods tend to contain less protein than meat, and in a form that the body finds harder to use, it is quite natural to wonder whether a vegetarian diet can meet all our nutritional needs. However, a varied vegetarian or vegan diet should supply more than enough protein, provided enough food is being eaten to meet daily energy needs.

All the amino acids humans require can be found somewhere in the plant kingdom, but you must choose foods from all the different plant groups - grains, pulses, roots, fresh green and yellow vegetables, nuts and seeds - so that the amino acids that are present only in small amounts in one group will be supplemented by those from another. The different sources of protein do not have to be eaten together but can be consumed at different times during the day.

Many traditional cuisines combined pulses with grains, such as beans or toast, hummous and pita bread, and lentil dhal with rice or naan.

A gratin is a dish with a crusty top, usually of cheese or breadcrumbs, baked in the oven and then finished by flashing it under a very hot grill, which gives it a gleaming brown topping. Gratins make excellent winter vegetarian dishes. Root vegetables, when combined with onions and cauliflower or broccoli florets, tomatoes, zucchini and corn kernels, make fine gratins. Extra protein can be added in the form of cheese and nuts, within the mix as well as on top.