Grilled lemon sole with Choron sauce

Ингредиенты

• 3 tbsp white wine vinegar
• 3 tbsp white wine
• 10 black peppercorns
• 2 tbsp shallots
• 1 tsp finely chopped fresh tarragon
• 1 tbsp water
• 1 tbsp tomato purée
• 3 free-range egg yolks
• 200g/7oz butter
• 1 tbsp finely chopped fresh flatleaf parsley
• 2 tbsp olive oil
• 8 lemon sole
• salt and freshly ground black pepper
• 1 tsp Dijon mustard
• 1 tbsp white wine vinegar
• 3 tbsp rapeseed oil
• salt and freshly ground black pepper
• 150g/5oz watercress