Over medium or medium low heat, sweat the shallots in a skillet or saucepan in the olive oil. If you want, you can get a little color (really sweaty) on the shallot, but do not brown them significantly.

Add the zest, salt, pepper and turn the heat up to medium for 20 seconds.

Add wine and reduce the liquid until you have about a tablespoon left (about 10-15 minutes).

Add the stock and reduce by half (about 15-20 minutes).

Add the cream and reduce until you have a thick, creamy sauce (about 15-20 minutes). Add ¾ of the lemon juice and keep warm; taste for salt and pepper.

Chop the tarragon (½ cup pre-chopped) and add 1-2 minutes before the fish is done.

Put all of the ingredients except for the fish into a large saucepan or dutch oven.

Fill with enough water to cover fish and bring to a boil. Do not put the fish in the poaching liquid yet. Just eyeball the amount of liquid to cover the fish.

Boil for at least 5 minutes and reduce heat to a low simmer.

Lightly salt and pepper the fish on both sides.

When sauce is ready (or about ready) put the fish in the gently simmering water and poach until opaque and beginning to flake. Depending on the thickness of the fillet, it should take around 8 to 11 minutes (no more than an inch thick).

Remove fish, pat dry with paper towels and plate. Spoon sauce over fish and serve.