Rocket or Arugula in American English is known as a salad vegetable which can be used as a substitute for lettuce. It has a nutty flavour, if you use young leaves, and they are good with a dressing of walnut oil. If the older mature leaves are used, they have a slightly bitter flavour and go well with a traditional vinaigrette dressing (white wine vinegar, olive oil and a mixture of herbs or just the herb of your choice). Rocket is usually used in Caesar Salads, and is great with all kinds of cheeses especially goats' cheese and gorgonzola. You can also steam rocket like spinach and use as a vegetable with others. The Italians love rocket and put it in meat sauces and with meats. A simple recipe is to spread rocket leaves with cream cheese and slivers of smoked salmon, roll them up and serve on a bed of rocket leaves. Its seeds can be used in cookery as a substitute for mustard seeds.