Salt-Baked Potato Salad from A Passion for Potatoes by Paul Gayler

Ingredients

• 2 tablespoons chopped walnuts
• 2 Granny Smith apples, cored and chopped
• 75 g (3 oz) cooked ham, cut into strips
• 1 celery stick, sliced
• Salt and freshly ground black pepper
• 75 g (3 oz) Roquefort cheese, crumbled
• 1 teaspoon Dijon mustard
• 2 shallots, finely chopped
• 1 tablespoon chopped tarragon
• 4 tablespoons olive oil
• 1 tablespoon cider vinegar
• 4 large floury potatoes
• ½ chicory head, cut into strips
• 25 g (1 oz) rocket