Salmon in Champagne Sauce
One 4-pound salmon fillet, skin on or with the skin removed (you can also use two 2-pound fillets)
3 large shallots, peeled and thinly sliced
2 cups fish stock (I like Kitchen Basics), or a mixture of 1 cup clam juice and 1 cup vegetable stock
5 tablespoons unsalted butter, divided use, plus a little more for greasing the roasting pan
6 tablespoons all-purpose flour
Salt and freshly-ground black pepper
2 cups champagne
2 egg yolks
3 tablespoons heavy cream
You’ll need a roasting pan that’s just a little bigger than the salmon fillet, and that can go in the oven, on top of the stove, and under the broiler. Use a little butter to coat the bottom of the roasting pan. Set the oven rack six inches below the broiler and preheat the oven to 425 degrees F.
Melt 1 tablespoon of butter in a large saucepan over medium heat, add the shallots and a little salt and stir to coat. Turn the heat to low, cover the pan, and let the shallots cook for 10 minutes. Remove the lid, turn up the heat, and cook the shallots, stirring, until they just start to brown. Spread the shallots in the buttered roasting pan to form a bed for the salmon.
Place the salmon fillet on top of the shallots, skin side up. Pour the champagne over the salmon. Put the pan on the burner and bring the liquid to a boil. Place the pan in the oven and cook for 10 to 15 minutes, basting twice. Check the salmon to see that it’s done to your liking – you may want to undercook it slightly because it will go under the broiler later.
While the salmon is in the oven, make the white sauce. Heat the fish stock in a small saucepan and set it aside. In the same saucepan you used for the shallots, melt 4 tablespoons of butter over medium heat. Add the flour, a half-teaspoon of salt, and some pepper. Whisk the flour into the butter, and continue to cook, whisking constantly, for 3 minutes. The flour will darken just a little. Add the hot fish stock slowly, whisking all the while. The mixture will come to a boil. Turn the heat to low, and continue to cook for a couple of minutes. Set the white sauce aside.
When the salmon comes out of the oven, tilt the pan to spoon out as much of the liquid as possible. Put it into the small saucepan you used before. Cover the salmon fillet with foil to keep it warm, and turn on the broiler. Bring the champagne liquid to a boil and reduce it a little bit. Whisk the hot liquid into the white sauce and let it sit off the heat for a couple of minutes. In a small bowl, whisk the egg whites and cream together. Add about a half cup of the white sauce/champagne to the egg yolk mixture, and whisk thoroughly. Add this mixture back into the pan with the rest of the white sauce/champagne, whisking constantly. Put the pan over low heat and cook the sauce for a minute until it gets a little thicker. Keep whisking it, and don’t let it boil. Taste it for salt and pepper, then set it aside off the heat.
Take the foil off the salmon. At this point, you should be able to take the skin off easily. Spread the sauce over the now-skinned salmon fillet, and once the broiler is hot, put the roasting pan in the oven. Broil the fish for 5 minutes, maybe a little more, checking carefully to make sure it browns lightly but doesn’t burn. If your broiler is small you may have to move it around to brown the whole thing. Take the pan from the oven and serve the salmon immediately.