If you are using frozen peas, partially defrost them; it is best to remove the casing from each broad bean unless they are very young and tiny as they tend to be leathery and tough once cooked. If you are using tender artichokes, cut the hearts lengthwise in quarters. Older, tougher artichokes should be stripped right down to their dish-shaped bottoms; these can then be cut into quarters or sliced horizontally into 2 or more pieces. In both cases drop each artichoke as soon as it is prepared into a bowl of cold water acidulated with the lemon juice.

Separate the lettuce leaves, removing the hard base, wash and dry them and cut into a chiffonade. Cut the peeled onion lengthwise into quarters and then slice very thinly.

Drain the artichokes and place in a wide, fairly shallow flameproof casserole dish or saucepan with the other vegetables, the whole but slightly crushed garlic clove and the sprig of thyme. Season with a little salt and pepper. Add 5 fl oz (150 ml) water and the olive oil.

Bring to the boil, cover tightly, turn down the heat and simmer very gently for about 15 minutes or until the vegetables are tender but not at all mushy.