Place the onions, carrots, celery, bay leaves, peppercorns, and salt in the bottom of a wide shallow pan.
1 cup carrots, 1 cup celery, 2 leaves bay, 8 whole black pepper corns, 1 tsp salt, 1 cup onion
Add 4 cup (1 L) water and bring to a boil over moderate heat.
Add the fish, plus more water if necessary to cover the fish, and simmer (do not boil) for 10 minutes.
4 in halibut steaks
Mix the cornstarch with a little cold water.
2 tsp cornstarch
Ladle and strain about 2 cups (500 ml) of the poaching liquid into a small saucepan and add the cornstarch mixture, stirring constantly over moderate heat until it boils and thickens.
In a separate bowl beat the eggs lightly, then add the lemon juice and beat until thoroughly combined.
2 large eggs, 4 tbsp lemon juice
Add a little of the thickened sauce to the lemon egg mixture, then add the lemon egg mixture to the saucepan.
Stir constantly until the sauce thickens, but DO NOT BOIL.
Carefully lift the fish out of the pan and serve covered with the sauce.
May be served either hot or cold but I prefer hot of a bed of white rice.
Notes
Note:Instead of Halibut, you can use other fish such as salmon, flounder, cod, or haddock.