Salad piemontaise

Ingredients

• 1 kg kipfler potatoes
• 3 large, firm tomatoes
• 200 g piece ham
• 50 g cornichons
• 1/2 cup flat leaf parsley
• 4 hard boiled eggs
• 1 cup good quality whole egg mayonnaise
• 1 tsp dijon mustard
• 1 tsp red wine vinegar
• freshly ground black pepper