Expert Advice

Oysters

Up there with caviar, foie gras and champagne as one of the world's ultimate luxury foods, oysters don't look much from the outside (the shells are rough and grey), but the flesh of these bivalved molluscs is wonderfully succulent and delicately flavoured, varying in colour from pale grey to beige, surrounded by a clear juice.

In Britain, the two main types available are Natives (grown in Whitstable, Colchester and Helford) and the less expensive Pacific (also known as rock or Gigas), which has a larger, longer shell.

In Ireland, the best native oysters are considered to come from Galway. You can also buy frozen oysters and tinned smoked oysters.

Availability
In the northern hemisphere, the old rule that native oysters should only be eaten when there's an 'r' in the month still holds true; so eat oysters from September to April.

During the summer months they're busy spawning, and their flesh becomes unpleasantly soft and milky. Rock oysters are available all year round.

Choose the best
Live, just-shucked (ie just-opened) oysters have the best flavour. If you don't want to shuck them yourself, you can ask your fishmonger to do it for you, but you'll need to eat them as soon as possible after that.

Although they tend to be smaller than rock oysters, natives are thought to taste superior - more complex, with a faint metallic note. They are graded by size, from 1 (the largest) to 5 and grow very slowly (they take three years to reach full size). They are more expensive than rock and tend to be eaten as simply as possible, so that their taste can be enjoyed to the full.

Rock oysters have a sweeter, salty, more unctuous flavour. Their larger size, and the fact that they're less of a strain on the wallet, means they're good for cooking with, as well as eating raw.

Prepare it
Scrub the live oyster shells with a stiff brush under cold running water, and discard any that are cracked or damaged. Any shells that aren't tightly closed, or whose open shells do not snap shut when tapped should also be thrown away, as the oyster inside is dead.

To shuck an oyster, wrap a tea towel thickly around your hand to protect it, then grip the oyster in the same hand, with the cupped shell down in the palm of your hand and the hinge pointing towards you. Insert a shucking knife (or, if you haven't got one, a short knife with a sharp, strong blade) into the small gap in the hinge and twist it from side to side until the hinge breaks. Lever open the top (shallower half of the) shell, then run the knife gently along the inner edges of the top shell to free the oyster. Discard this shell. Using the knife, gently free the oyster from the muscle that binds it to the deep shell, to leave the oyster sitting in its juices. Pick out any fragments of broken shell with the tip of the knife, but try not to spill any of the juice.

Frozen oysters should be defrosted for at least four hours in the fridge, then eaten straight away.

Store it
Cover live oysters with a damp tea towel and put in the fridge with the larger side down. They will keep up to three days, but the sooner you eat them, the better they'll taste. Shucked oysters should be kept covered in the fridge, and eaten on the same day as purchase.

Cook it
Arrange them on a bed of ice and serve raw, just as they are, or with lemon juice, a French-style shallot vinegar, one or two drops of Tabasco or mirin (Japanese rice wine).

Top with breadcrumbs, herbs, and grated parmesan and grill (2-3 minutes); pan-fry, poach or steam (2-3 minutes).

Bake in a traditional Irish steak and oyster pie. Use to make angels on horseback (wrap in bacon, pancetta or Parma ham and roast (6 minutes).

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Cauliflower

A brassica, like cabbage and broccoli, cauliflower is a mass of tiny, tightly packed flower heads (called curds), which grow from a thick central stem to form a single, round head, cupped by green leaves. It has a firm, almost waxy texture, and a mild, delicate flavour. Most cauliflowers are white, but it's also possible to find green and purple varieties, as well as the sweeter Romanesco cauliflower, with its distinctive pointed florets. Like all brassicas, cauliflower smells very unpleasant if overcooked, so brief cooking is essential.

Availibility
All year round, but at its best from mid December through to mid April.

Choose the best
Go for cauliflowers with pure white heads with no discolouration, and crisp green leaves. The colour of the base is a good indication of how recently it's been picked - the whiter, the fresher.

Prepare it
Cut off the surrounding leaves (if they're fresh, they can be cooked, too). For large cauliflowers, cut off individual florets from the central stem and cut again if necessary. You should end up with florets of a comparable size, so that they all cook at the same pace. Then wash. Smaller, baby cauliflowers can be cooked whole.

Store it
In a perforated bag in a cool dark place, or the fridge. It will keep for several days.

Cook it
The florets are great used raw in a salad or as part of a crudité selection served with dips. Cooked cauliflower florets keep their shape best when steamed (5-10 minutes) - remember to place them upright in the steamer. It can also be boiled (takes 5-10 minutes for florets; around 10 minutes for a whole cauliflower). For both cooking methods, test regularly with the tip of a knife to make sure they don't overcook.

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Lamb

A lamb is a sheep that is under one year old, and is known for its delicate flavour and tender flesh.

Young lamb is slaughtered between 6 and 8 weeks - it is the palest of all lamb. Spring (also called early or summer lamb) is 3 to 5 months old. Lamb between 1 and 2 years is called 'hoggart' - it has a stonger flavour and slightly less tender flesh; anything over 2 years is called mutton, which has much more flavour - but also a tougher flesh that needs slow-cooking to tenderise it.

The older a lamb, the deeper the colour of the meat, though the time it has been hung for and the breed that it comes from will also make a difference.

Availibility
All year round.

Choose the best
Always buy lamb from a source that you trust - a good supermarket, local butcher, farmers' market or shop, or a website mail order company. Of those five sources, the last four are more likely to be able to tell you the most about the meat, for example, where it comes from, how it was reared and slaughtered. Traceability like that is crucial in ensuring that the lamb you are buying has been humanely treated while alive, had the shortest possible journey to the slaughterhouse (long journeys are highly stressful for all livestock) and has been expertly handled once salughtered - all of which will have an impact on the meat's flavour and tenderness.

Organic lamb, and lamb from rare breeds, is the most expensive, as the highest farming standards should have been adhered to at all stages of the animal's life. The length of time that a lamb has been hung for will also determine how flavoursome and tender it is, about 8 days is best.

Read more about animal welfare in general at Sustain, the alliance for better food and farming.

Many different cuts of lamb are available - which you buy depends on how you want to cook it. For roasts, the best cuts include leg, breast, best end of neck (also known as rack of lamb), shoulder, saddle, rump and loin.

For quick cooking, choose fillet, chump chops, loin chops, leg steaks, best end cutlets and butterflied leg. For slow cooking, leg, shoulder, shank, neck and chump chops are among the best options.

Lamb is also available minced (good for pies and burgers) and you can also buy lamb offal (mainly the kidneys and liver but also, less commonly, the heart and the sweetbreads), which is quick to cook, cheap and nutritious.

When choosing any cut of lamb, look for firm, fine-grained meat with a velvety texture; it should be moist, rather than dry or slimy. Any fat on the outside of the lamb should be white (fat that is yellow might well be rancid). Properly hung lamb should have a deep red, rather than bright red colour, although very young lamb will be paler than older lamb.

Prepare it
If desired, certain cuts of lamb can be marinaded, to add flavour and moisture and to tenderise a little further. Before it goes in the oven, lamb should be at room temperature, so take it out of the fridge 30-60 minutes before cooking. Keep it covered, in a cool place.

Store it
Unless the lamb is vacuum-packed, take off the packaging or wrapping (making a note of any use-by dates beforehand) and put the lamb at the bottom of the fridge on a dish that is large enough to contain any drips (vacuum-packed lamb should be kept in its packaging). Make sure the lamb doesn't touch any cooked foods or anything that will be eaten raw.

Any cuts that are bought loose will keep for up to 2-4 days. Larger cuts for roasting will keep up to 5 days. Minced lamb or lamb offal should be eaten within a day of purchase. For vacuum-packed meat, follow the use-by date on the packaging.

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Brought to you by the experts from BBC Good Food magazine

For more information on growing your own fruit and veg, visit BBC Gardeners' World Live which takes place at the same time as the BBC Summer Good Food Show.