Fish Stock

Debone the fish, cut the trimmings into smaller pieces. Place them in a bowl along with the heads and rinse thoroughly to remove any small impurities.

Cut celery, parsley, fennel, leek, and onion into 1 cm cubes. Halve the mushrooms.

In a pot over medium heat, melt the butter. Add parsley, leek, onion, and celery and sauté for 2 minutes, stirring constantly. Add fennel and sauté for another minute. Add mushrooms, salt, and wine, and reduce to 1/3 of its volume.