1 large cos or 2 large butterhead lettuce (or the outer leaves from four or more lettuces)
1 medium onion, chopped
salt and pepper
5-6 fresh lovage leaves (plus 4 more to garnish) or 3-4 sprigs fresh tarragon
a little butter or olive oil
1L/1戮pt good chicken or vegetable stock
250g/9oz (shelled weight) fresh or frozen peas