Salt and freshly ground -black pepper Preparation time: 20 minutes Freezing: not recommended Peel and chop the avocado and place it in a mixing bowl. Sprinkle it with the lemon juice to prevent it from discolouring. Halve the melon, discard the seeds and scoop out the flesh using a melon baller (or cut it into cubes). Gently combine the melon, chopped celery, strawberries and prawns with the avocado and refrigerate until needed. Meanwhile, puree the dressing ingredients in a food processor or liquidiser. Arrange the lettuce on 4 plates and divide the prawn mixture between them. Pour the dressing over and serve immediately. Cook's notes: when melons are ripe they should 'give' slightly when pressed at the stalk end. Wrap up melons well if storing them in the refrigerator as otherwise they will permeate everything around them with their heady scent.