1. After thoroughly washing the bones, head and skin of the fish, roughly crush the fish bones and trimmings with scissors. Chop the onion. Cut the carrot. Cut the leek into slices.
2. Melt a little butter in a saucepan.
3. Add the vegetables to the pan. To stiffen the edges, ornaments and heads of fish in the butter, without grabbing or coloring.
4. According to the recipes envisaged add white wine or Noilly. Add the white wine, pepper, salt, thyme, bay leaf and water.
5. Bring to a boil for 20 minutes and skim.
6. At the end the cooking passes to Chinese without treading.
7. Cut more or less to add flavor.