Prawn Salad with Tarragon

Ingredients

• 150 millilitre (1/4 pint) mayonnaise

• 2 tablespoons Greek yoghurt

• 1 teaspoon Tarragon

• 350 gram (12 ounce) cooked, peeled prawns

• 1 stick of celery, thinly sliced

• 1 red eating apple, finely diced

• 2 large leaves of iceberg lettuce

• 1 tablespoons flaked almonds, toasted