In the UK supermarkets generally stock a range of onions. Most onions have been left to dry and are ideal to keep for some time, no matter what the date says. Just keep them in a cool dark place. My favourite spot is a ventilated box in the garage. Yellow onions, also known as brown onions, are an all rounder that are very sharp when raw, but release their natural sugars when cooked. This is the type of onion I have in the kitchen all year round for soups, sauces, stir fries, pasta and curries. A great sauce with lamb is French sauce soubise or onion sauce or an onion tarte tatin. Spanish onions are large, sweeter onions. They are more difficult to find, but are delicious raw or cooked. They tend to be more expensive, so I choose not to buy them generally. Red onions are delicious raw in salads, for making chutney and using in kebabs. Perfect for summer eating in a Greek salad. Shallots are an absolute essential in French cooking. I prefer the long banana shallots, as they are marginally easier to peel than the smaller round shallots. Sweet and delicious, they are perfect in sauces such as duck confit with redcurrant sauce. Then there are spring onions, also known as green onions. The obvious choice is salads, but they go particularly well with fish, when you want the flavour, without overpowering the dish. Try salmon and broccoli quiche, poor man's lobster with thermidor sauce, or French peas. Of course, farmer's markets and other shops will stock other varieties - I particularly love the red spring onions we used to get in France, but nowadays cost is an issue. The good old faithful yellow or brown onion is staple for flavour in most dishes.