1.Heat a medium frying pan over high heat. Cook prosciutto for 2-3 minutes until golden and crisp. Drain on paper towel.
2.In a large bowl, arrange watercress, apples, blue cheese, almonds and prosciutto.
3.To make cider vinaigrette, whisk together all ingredients in a small jug. Season to taste. Drizzle over salad just before serving. Serve salad with crusty bread.
It is vital salad greens are dried well after washing. Do this by using a salad spinner, or pat dry with paper towels or a clean tea towel.