1.In a medium bowl, combine beef, parsley, mayonnaise, cornichons, mustard, capers, anchovies and eschalot. Season. Divide and shape mixture into 4 flattened patties. Cover and chill until required.
2.Heat oil in a large non-stick frying pan on high. Cook patties 2-3 minutes each side until cooked through. Drain on paper towel.
3.Spread toasted buns with extra mustard and mayonnaise. Place watercress and slice of blue cheese on base of each bun. Top with beef patties, chutney and remaining bun halves.
You can replace blue cheese in the recipe with cheddar or brie if preferred.