Truite au bleu

Method

1. 1 Only use very fresh fish and do not wash the fish; the slime on the skin is what gives it its blue color.
2. 2 Boil water with carrots, onions, and thyme for 15 minutes to make vegetable broth.
3. 3 Pour the red vinegar into the broth and heat it to 80 degrees Celsius, but do not let it boil.
4. 4 Place the whole fish in water, and its skin will immediately turn a silvery-blue color.
5. 5 Boil for 8 minutes at 80 degrees; the skin will crack and lose its green color if the water boils vigorously.
6. 6 Remove the fish from the pot, then drizzle with melted butter mixed with lemon juice and parsley, and serve with boiled potatoes.