Ingredients
Turbot, eel, pike, tench, and trout, 500 g (about 1 lb) each; 300 g (about 10 oz) mushrooms; 40 g (about 3 tablespoons) butter; 40 g (about 1/3 cup) flour; 3 eggs; 2 small pearl onions; 500 ml (about 2 cups) fish stock.
Seasonings
1 bouquet garni (bay leaf or thyme), 1 carrot, 1 leek, 1 onion, salt, pepper, and fresh cream to taste.
Instructions
1. Finely chop the onions and shallots; slice the carrots and white parts of the scallions; thoroughly scale the fish, clean out the cavity, rinse well, and cut into pieces.
2. Grease the bottom of a skillet with butter, add the vegetables and fish stock, then arrange the fish pieces in the following order: eel, pike, tench, perch, and finally trout. Simmer over low heat for about 20 minutes.
3. Mix butter and flour into a paste, then whisk in the strained cooking liquid to form a sauce; stir in egg yolks and whipped cream, being careful not to let it boil, and finish by folding in mushrooms quickly sautéed in a little butter.