Lettuces vary greatly in colour and texture: from light green to deep red, from those with loose, floppy leaves to those with crisp leaves and firm stems. Lettuce is mainly used fresh in salads or sandwiches but can also be cooked. In France, lettuce is cooked with baby onions and peas in stock and in China, lettuce is a common cooked vegetable. In a green salad, lettuces are generally interchangeable, but when adding other ingredients, pick a leaf type that will suit them—floppy leaves won’t go well with heavy ingredients like potatoes, and crisp firm leaves need a fairly robust dressing. Always dress lettuce just before you serve it.