To the arboisienne blue-cooked trout

Ingredients for 4 people:
4 freshly fished trout, of 150 to 200g
30 g of butter,
4dl of vinegar of Vin Jaune,
salt, pepper, curly parsley.

Recipe:
empty trout without wash them or wipe them off, so they have their blue hue.
Vinaigrer the Court bouillon with vinegar of Vin Jaune.
Put trout in the broth by boiling for 5 minutes.
Prepare a melted butter and serve with parsley in Crown on a plate.