Prawn and pink grapefruit salad

Serves 8

I've used uncooked fresh Red Sea prawns here with their heads on, so that you can keep the shells and freeze them for the soup that I'll be cooking up in next week's column for a Boxing Day or New Year's Day brunch.

1kg medium-sized raw prawns with their heads on
250-300g small, tasty salad leaves like land cress, rocket, pea shoots, etc
3-4 pink grapefruits, peeled and segmented and any juice reserved
2tbsp sea salt

For the dressing

The juice from the grapefruit

1tbsp cider vinegar
2tsp Tewksbury or Dijon mustard
6-7tbsp rapeseed oil
Salt and freshly ground black pepper

Bring a pan of water to the boil, large enough to accommodate the prawns and add a couple of tablespoons of sea salt. Cook the prawns for 2-3 minutes, then drain and leave to cool. Remove the heads and peel the tails and put them in the freezer for a Boxing Day soup.

Put the grapefruit juice in a pan and simmer it until you have about a tablespoon left, then pour it into a mixing bowl with the vinegar and mustard and gradually whisk in the oil and season to taste.

To serve, arrange the leaves on serving plates with the prawns and pink grapefruit and spoon the dressing over.