Cooking with citrus

An essential ingredient

Here we all are, waxing lyrical about seasonality, yet no cook would dream of doing without citrus fruit, whatever the time of year. In their many forms, these exotic fruit have become essential to the way we cook.

Bitter Seville oranges and spice-sharp blood oranges, hailing mostly from the Med, still have a limited season, but limes and oranges, lemons and grapefruit are with us year-round.

Because they're always going to be imported (surely more eco-friendly than growing them in heated greenhouses in the UK), we need feel no more uncomfortable about making a jug of lemonade in the heat of summer, than about boiling up a preserving pan of marmalade in the depths of winter. No kitchen should ever be without them.

Citrus traits

With their padded protective skins, citrus fruits could have been designed for export. They keep exceptionally well, staying juicy for weeks. Choose citrus fruit that are firm and bright-looking; dull skins and soft patches indicate fruit that are past their best.

To prolong their lifespan, most are coated in a light wax. Although it's tasteless and harmless, it's still advisable to rinse fruit in warm water before using the fragrant zest. Some unwaxed citrus fruit are sold in sealed plastic pouches to reduce dehydration, and are best stored in the fridge and used speedily. Waxed fruit will be quite happy in the fruit bowl.

The coloured outer layer of citrus fruit, the zest, contains scented essential oils that impart a handsome flavour to dishes. Either peel off in wide strips with a vegetable peeler, or grate finely. Take as little of the bitter, underlying white pith as possible with it. Remember to remove zest before cutting and squeezing - it's almost impossible afterwards.

To extract the maximum juice either roll citrus fruit around on a flat work surface, pressing down firmly with the palm of your hand (particularly useful for limes, which can be hard to squeeze), or warm through gently by dropping into a pan of hot water, popping into the microwave for a few seconds, or even placing in a warm oven for a minute or two. Once squeezed, fresh citrus juice should be used the same day to reap its lively benefits.

Familiar fruits

Lemons

The lemon is the ultimate citrus fruit, full of tart, sunlit juice, ready to dispense its blessings to sweet and savoury dishes and to drinks hot and cold. Its golden juice is a miracle-worker, bringing life and light to anything from a grilled fillet of fish to a devastatingly rich lemon posset.

Use it with olive oil and oregano to breathe Greek flavour into any salad, squeeze onto free-range chicken before roasting, or over sautéed courgettes or freshly boiled broad beans. A squeeze or two can brighten up dull sauces or soups, highlighting inherent flavours.

Lemony puddings come in many forms, rich with cream or pure and light. Real lemon sorbet is divine and so too is lemon ice cream. Top a scoop or two with raspberry or strawberry coulis, an optional shot of grappa or vodka and top up with sparkling prosecco or cava. Wow.

Lemon zest knocks the socks off so many other flavourings. Use in marinades, stuffings, dressings, cakes, biscuits, trifles, soufflés, rice puddings, poached fruit or buttery breadcrumb crusts for fish or lamb. For the ultimate pick-me-up for any number of savoury dishes, stews especially, knock up an Italian gremolata - finely grated lemon zest mixed with finely chopped parsley and garlic - and sprinkle over minutes before serving. It works every time.

Oranges

Oranges are another mega-presence in the citrus firmament. Their natural sweetness (in theory, at any rate) pushes them towards the realm of the pudding, but orange juice can work nicely in savoury dishes, when used carefully, particularly with fatty meats such as pork, goose and duck. Use it in marinades and sauces.

Orange segments, slices or chunks are often welcome in savoury salads. Try mixing with watercress, chicory and toasted walnuts, or alternating slices of orange and tomato, scattered with black olives or paper-thin slices of shallot or red onion, or mix with cooked beetroot, watercress and toasted pine nuts. Dress with lemon (or white wine vinegar) and olive oil.

One of my top winter puddings is that old favourite, caramelised oranges, which shows off sweet oranges at their purest. Orange and chocolate is bliss for some, desecration for others - tread carefully. Both zest and juice are fabulous in cakes and icings and, for something unusual but totally more-ish, try a boiled orange cake (Claudia Roden’s recipe started the trend in this country).

Dried strips of orange or tangerine zest are surprising and unusual flavourings, used in the south of France in beef daubes (stews) and in Chinese cooking. Dry your own on a rack in the bottom of a low oven, or strung up in a dry airy place. Store in an airtight jar.

Seasonal stunners

Blood oranges

These have been tamely rechristened 'ruby red oranges' but don't let that put you off. During their short season in late winter make the most of their thrilling, spicy tartness. Freshly squeezed blood orange juice is a sure way to get going on a cool and miserable morning (stir in a little sugar if necessary), but they also make zingingly beautiful puddings.

They can replace oranges in most desserts, though I particularly relish them in jellies (add a shot or two of orange liqueur for the grown ups) or peeled and sliced, then marinated in a thick sugar syrup flavoured with chilli or spices or even a few sprigs of rosemary, to bring out their spiciness.

Kumquats

The smallest and weirdest of the common citrus fruit. Perversely, the skin and zest are sweet, while the juicy insides are tart with a hint of bitterness. A winter treat, they can be eaten whole, just as they are (you'll either love them or loathe them) or cooked with sugar, spices or spirits to make sweet compotes for pudding or aromatic chutneys to partner duck and other fatty meats.

Seville oranges

Available only in the winter months, these are mainly sold for marmalade making, but can and should be used in other ways. I love them with fish, especially large-flaked white fish, but their tart orange flavour is also a winner in puddings - try adding to a rich custard or a steamed sponge. Use juice and/or zest to season green veg such as spinach, spring greens or leeks.

Small size, big flavour

Tangerines, satsumas, mandarins, clementines and clemenvillas (a fairly widely sold form of clementine, slightly larger than other tangerines and the like) are the most approachable bunch of the citrus family. Neatly fitting into the palm of the hand, they can be peeled and eaten in minutes, releasing a brief burst of sweet fragrant oranginess. Although usually eaten just as they are, they are surprisingly good cooked.

Peel and slice with a sharp knife into thick discs, then poach with dried fruit for five minutes. Delicious served warm or cool with thick Greek yoghurt or on cereal for breakfast. Alternatively halve, unpeeled, and roast for 30 minutes alongside goose or duck.

Bittersweet fruits

Grapefruit

Once reserved for breakfast, halved and maybe grilled into warmth, the grapefruit deserves wider recognition. It's superb in savoury salads; try it with crisp Chinese cabbage and toasted sunflower seeds, or rocket and smoked chicken. The pink varieties look dead glamorous, and tend to be sweeter. 'Sweetie' is a green-skinned form of grapefruit and, as its name suggests, tastes sweeter than the rest.

Pomelo

A giant among citrus fruit, but most of its bulk is composed of thick white pith. If you want to try your hand at candying citrus peel, this is ideal. The segments, once you reach them, are firmer than those of other grapefruit and are best individually peeled. The result is an almost crisp form of sweet grapefruit that's most appealing.

Ugli

Truly the least handsome of the bunch, with a baggy, dirty yellow skin - but the taste makes up for visual deficiencies. Juicy and fragrant, complete with a touch of bitterness but more dominantly sweet.

Recipes

They come in a myriad colours and sizes, but all citrus fruits are great for cooking, adding zest to sweet and savoury dishes and in marinades.

Sweet dishes

• Lemon posset with lemon shortbread by James Martin
• Caramelised oranges with honeyed ricotta (video recipe) by Sophie Grigson from Get Cooking
• Citrus tart with rich shortcrust pastry (video recipe) by Lesley Waters from Get Cooking
• Key lime pie by Emma Crowhurst
• Seville orange meringue pie by Mary Berry
• Hot lemon curd soufflés by Delia Smith
• Lemon surprise pudding by Sophie Grigson
• Spiced kumquats by Patricia Lousada
• Orange pudding by Claudia Roden

Savoury dishes

• Avocado and orange salad by James Martin
• Mexican fish tortillas by Sophie Grigson
• St Giorgios kleftiko parcels by Ainsley Harriott
• Chicken with roasted garlic by Neneh Cherry and Andi Oliver
• Osso buco Milanese style by Anna Venturi
• Salmon ceviche with fennel salad by Stuart Gillies
• Pomelo salad by Ross Burden
• Chicken skewers with lime and coriander dip by James Martin

Citrus marinades

• Lemon and dill-marinated salmon with herb salad by Brian Turner
• Grilled marinated chicken, Khmer-style by Sri Owen
• Marinated feta with panzanella by Lesley Waters