I love this recipe for its flexibility and simplicity. It's also the perfect showcase for flawless, high quality fish. There are no bells & whistles. It's simple, fresh, and can be made ahead of time - making it great for entertaining. You can be flexible with the herbs -- I used what's fresh and growing in my garden, but feel free to play around.
3 cups water
2 bay laurel leaves (dried or fresh)
1 rib celery (preferably an inner rib with leaves)
8 sprigs mixed spring herbs (I used chervil, lemon thyme, and tarragon -- parsley is a nice substitute for the chervil if you have a hard time finding it but it does add a nice anise scent)
1 1/4 cup dry white wine
1/2 lemon (juice and zest)
3/4 teaspoon salt plus additional for seasoning salmon
1 1/2 lbs wild Coho salmon side, skin-on (you can substitute filets)
Extra herbs for garnish.
Herbed Butter Sauce for serving (optional, recipe below)
If you have a long gratin dish that is stovetop safe, use it. Otherwise a large dutch oven or deep fry pan will also work. Bring water and aromatics/herbs to a boil in the pan just mentioned. Once boiling, remove from the heat, cover with foil or a lid and let steep for 10 minutes. After steeping, add wine, lemon juice, zest and salt. Allow to cool at least another 10 minutes.
Meanwhile, season the salmon with about 1/2 teaspoon flaked or semi-coarse salt and a grind of fresh pepper. If needed, trim the salmon slightly to fit in your pan. If you're using a side, you can shave off or trim the sinewy layer over the belly fat (or leave as is). Any trimmings you can cook later or set it aside for a salmon scramble the next morning.
At this stage you can either proceed with cooking the fish, or refrigerate the herb stock until you're ready. Either way, start with the stock at room temperature. Slide the fish into the pan, skin side down, making sure it is completely covered with liquid. If not, add additional water or wine. If you add more than a 1/2 cup, add an extra 1/4 teaspoon of salt.
Place the pan with stock and fish over a medium low burner (low if your stove is hot) and very slowly cook the fish - spooning liquid over the top if it becomes unsubmerged. If you start to see white fat right off the bat, turn down the heat. The skin helps to insulate the fish from cooking too quickly -- therefore if you are using fish without the skin, be extra careful to make sure the heat is low and cook for less time. From the time you start the heat to the time the fish is done should be no more than 8-10 minutes (with skin) - but be careful not to overcook if your heat is strong. Do not let the mixture boil - it should be just below a simmer by the time the fish is ready. Keep in mind your fish will continue cooking after you turn off the heat so err on the side of undercooking.
While the fish is resting make the butter sauce using the herb stock. Garnish with a small handful of roughly torn herbs. Serve with cous cous, farro salad, or roasted potatoes, and the veloute sauce on the side .
*Fish can be made several hours or a day ahead and stored in its broth in the refrigerator. Warm gently in the broth over the stovetop prior to serving.
Herbed Butter Sauce
This simple butter sauce, known as a veloute, is as easy as it gets for pan sauce. You're making a simple butter/flour roux and whisking in the leftover stock from cooking the fish. I figure you've already done the work making a gorgeous stock, why not max out the benefits with a sauce. Either way, don't discard the broth -freeze it or refrigerate for a risotto or fish chowder.
1 1/2 cup poaching liquid
3 tablespoons butter
1 tablespoon flour
Reduce the poaching liquid by about half by boiling it over high heat. Meanwhile, warm butter over medium heat in a small, separate pan, then add flour and whisk until smooth. Continue cooking for 2-3 minutes. Slowly add the reduced stock, whisking constantly. The sauce will thicken. Keep adding until desired consistency is reached. If the sauce is too thick, add a little additional stock. Finish with a large squeeze of lemon juice and additional salt and pepper if needed (keep in mind the stock was pre-salted). If plating the fish, serve poured atop each piece. Otherwise I prefer to present the whole fish in its liquid and serve family style. Put the sauce in a warmed saucer so each person can add as much or as little as they like.