Serves 4.

8 filets of sole
1 carrot, 1 onion, sliced
Bouquet garni
Salt and pepper
1-1/4 cups dry white wine
1 cup of mushrooms, sliced
2 Tbsp of butter
Lemon juice and parsley
Sauce hollandaise
2 egg yolks
4 oz. of unsalted butter (at room temperature and cut into small pieces)
2 tsp of lemon juice, salt and pepper 

• Preheat the oven to 350°F.
• Place the filets, folded in half, in a shallow fireproof dish with the carrot, onion, bouquet garni, salt and pepper.
• Pour over the wine, cover with buttered wax paper and poach in oven for 15 to 20 minutes.
• Transfer the filets to a serving platter and keep warm in the turned off oven.
• Pour the cooking liquid in a saucepan and reduce to 2 Tbsp.
• In the meantime, place the mushrooms in a small pan with the butter, lemon juice, salt and pepper.
• Cook gently for 5 minutes or until tender.

For the sauce hollandaise

• Lightly beat the yolks in a heavy saucepan.
• Strain the reduced cooking liquid of the soles in the egg yolks.
• Mix well.
• Place the saucepan with the egg mixture in a larger saucepan filled with 1/2 inch of simmering water.
• Keep the heat low and whisk the mixture continuously until a thick creamy consistency is obtained.
• This is the double boiler method.
• With careful attention to the heat, try to do without.
• Beat in the butter a little at a time.
• Do not allow the sauce to get to hot.
• When all the butter has been added, stir in the lemon juice and season to taste.
• Stir in the mushrooms and parsley.
• Keep warm.

To serve

Make sure to remove additional liquid from the cooked filets.  Coat the filets in the serving dish with the hollandaise sauce. Put the filets of sole under a very hot broiler until the top is lightly browned. This must be done very quickly.  Serve immediately.

The vegetables can be kept under the fish, or they can be saved and puréed to make a soup with the addition of some fish stock and béchamel sauce.