Easiest way to make bistrot style fish quenelles with a sauce to die for

These bistro-style fish quenelles are made with a langoustine and cognac cream sauce. Learn this simple technique to make restaurant quality quenelles of any type. INGREDIENTS Enough to make 4 to 8 quenelles depending on size. For the quenelles: 200 - 250 g/ (7 - 8.8 oz) fish fillet (a fresh fish with firm flesh) 2 eggs 150 ml (5 fl oz) pure cream (heavy whipping cream) 60 g (2.1 oz) plain butter (ensure the butter is soft and cut in cubes) Salt, pepper and cayenne pepper for seasoning. To poach the quenelles: (use a spoon plunged in hot water to shape the quenelles). A large pan with plenty of simmering water. Add the following ingredients: 1 garlic clove cut in half A small twig of thyme 2 pinches of salt. For the sauce: 200 g (8.8 oz) langoustines or tiger prawns or any other crustaceans (bruise the shells with a rolling pin prior to cooking) 1 good tbsp of butter for cooking 1 tbsp carrot (cut in rough cubes) 1 tbsp celery roughly chopped. 20 g (0.7 oz) shallots roughly sliced 1 tbsp finely sliced leek (white part) 1 garlic clove (bruised) 1 tsp tomato paste 2 tbsp cognac Salt and pepper to season 300 ml ( fl) oz fish fumet reduced to 150 ml / fl oz 200 ml ( fl oz) pure cream (heavy cream)