Mangetout, also called snow peas, get their name -- translated from French, it means "eat all" -- from their characteristic edible pods. Technically unripe, the pods and their undeveloped peas are eaten together, either raw and crunchy or cooked to soften and sweeten but still retain a little bite. Mangetout only need to be cooked for a few minutes. Don't overcook these delicate vegetables -- doing so turns them soggy and causes the pods to split open. Prevent this is by taste-testing as you cook.
Mangetout are picked before the peas ripen and the pods become thick and inedible, which also means they don't develop the unpleasant string you get with regular pea pods and green beans. The lack of a string makes preparing mangetout quick and easy -- rinse them under cold water, then slice off the tops and tails with a sharp knife. You just need to cut off and discard the very ends of the mangetout. They are then ready to eat as-is, serve in a salad or cook. If you are cooking mangetout with or alongside other vegetables, wash and top and tail them in advance so they are ready to throw into a pan as soon as it's time for them.
Boiling mangetout is a simple process -- boil water in a pan, add a little salt, slide the mangetout into the pan and remove them after a minute or two. This simplicity belies the fact that when boiling mangetout, the difference between perfect crispness and waterlogged sogginess is only a matter of seconds. Stand by the pan, put a timer on for 60 seconds and keep a slotted spoon handy. When the timer goes off, remove and taste a mangetout. If it's still a little too crisp, boil for 30 seconds more before tasting again. As soon as the mangetout are done, remove them from the boiling water with the slotted spoon or pour the contents of the pan into a colander. If you want to add mangetout to a sauce or soup that is already simmering, throw them into the pan for only the final few minutes of cooking.
Steam mangetout to avoid the risk of waterlogging that comes with boiling. Although steaming is a gentle method, it still only takes minutes for mangetout to cook. Use an electric steamer, a stacking steamer and saucepan set, a bamboo steamer or a collapsible steamer basket inside a lidded saucepan. Add only a few inches of water to the pan and bring it to a simmer. Make sure the water level is underneath the steamer's holes so the simmering water doesn't come into direct contact with the peas. Arrange the mangetout evenly in the steamer basket, cover with a lid and test one after two minutes. Steam for another 30 seconds before testing again, if necessary. Remove the steamer basket from the heat, or the mangetout from the basket, as soon as they're done.
Stir-frying is the best way to cook mangetout while adding a little flavor to it. Use a combination of butter and oil or an infused oil to impart a subtle hint of flavor without overwhelming the natural taste. Let the oil heat up in a frying pan or wok before adding the mangetout. Keep the heat at medium-high and stir the mangetout constantly for one to two minutes total. As with other mangetout cooking methods, tasting is the best way to determine if they're done. If you are adding mangetout to a mixed vegetable stir-fry, start with any vegetables that take longer to cook, such as onions and bell peppers, and add mangetout only for the final few minutes of cooking.