Salmon with Spinach Butter Sauce recipe.
Oven Poached Salmon with Spinach Butter Sauce
Prep Time
15 mins
Cook Time
30 mins
Total Time
45 mins
Fish wrapped in foil or parchment paper packets, en papillote, then baked in the oven is a great way to cook fish. The fish stays moist and the natural juices accumulate in the pouches. The spinach butter sauce adds a luxurious element and compliments the fish nicely. Perfect with boiled baby potatoes. This recipe is slightly adapted from The Forgotten Skills of Cooking by Darina Allen
Course: Dinner
Cuisine: Irish, Irish American
Keyword: oven poached salmon, salmon
Servings: 4 -6 servings
Author: Ginger
  • 5 oz (150 g) baby spinach
  • 2 lbs (1 kilo) salmon filet or two sides of arctic char
  • Kosher Salt
  • 4 tarragon sprigs divided
  • Fennel Fronds optional
  • ¼ cup (60 ml) dry vermouth or dry white wine optional
  • 5 Tbs butter plus 1 Tbs
  • 1/2 cup (125 ml) heavy cream
  • 1 lb (455 g) fingerling potatoes
  • 1 -2 TBS Extra virgin olive oil
  • About 1 TB minced chives
  • About 2 TBS chopped parsley
  1. Preheat the oven to 375˚F / 190˚ C / Gas Mark 5
  2. Wash and remove the stems from the spinach. Blanch the spinach in salted boiling water for one minute after the pot returns to a boil. Drain the spinach then shock in ice water. Place the blanched spinach on a clean flour sack towel, or thin kitchen towel, to dry, then squeeze out all the water from the spinach. Finely mince the spinach and set aside.
  3. Cut a piece of aluminum foil that is at least 6-8 inches (20 cm) longer in length, and wider, than your piece of fish. Lay the aluminum foil on a sheet pan, large enough to hold your piece of fish, and smear half a tablespoon of butter across the center part of the foil. Place the salmon on the buttered surface and smear, or dot, the surface of the salmon with a half tablespoon of butter. (If your piece of fish is larger or you're a cooking a whole fish, you will need more butter). Sprinkle the salmon with salt and scatter half of the tarragon leaves over the salmon and some fennel fronds. (If you are cooking a whole fish, add the herbs and salt in the cavity of the fish). Add the vermouth or wine if using.
  4. Cover with another piece of aluminum foil and fold in and crimp the 4 sides of the foil to create a tight seal.
  5. Place the fish in the preheated oven and bake for 20-30 minutes, depending on the size and thickness of your fish. Start checking to see if your fish is done at 20 minutes. Press down on the top of the salmon at its thickest part. If it feels tender but firm with some give, then the salmon is done. Once the salmon is done, take it out of the oven and let it rest in the foil for 10 minutes. You can take the salmon out of the oven slightly before it is done, as it will continue to cook while it rests.

  6. In the meantime, mince the remaining tarragon and set aside.
  7. Boil some salted water in a saucepan large enough to hold all your potatoes. Add the fingerling potatoes, whole, to the salted boiling water and cook until done. Depending on the size of the potatoes, they could be done between 10 and 20 minutes. The potatoes are done when you pierce them with a knife, and the knife slides easily in and out of a potato without resistance. Check several potatoes to determine if they are all cooked. Drain the potatoes, and when cool enough to handle but still hot, cut the potatoes in half lengthwise. Lightly drizzle with olive oil, chopped parsley, and minced chives.
  8. While the salmon and the potatoes are cooking, make the spinach sauce. Add the heavy cream to a wide mouth saucepan and turn the heat to medium-high. Carefully bring the cream to a boil. Once the cream starts to boil turn the heat slightly down, simmer until the cram is reduced by half its volume, ¼ cup. Once reduced, add the minced spinach and remaining tarragon and stir to combine. Reduce the heat to low then add the butter, one tablespoon at a time, to the sauce and whisk in completely. Once the butter is thoroughly whisked in, add another knob of butter then whisk and repeat whisking it in. Repeat until all the butter is emulsified in the sauce. While you are making the sauce, watch the heat carefully and whisk constantly, you do not want the butter to get too hot or it will separate or brown. Once the fish is rested, carefully pour out some of the juices from the fish into the sauce, then whisk until combined.
  9. Place the fish on a platter and spoon the spinach butter sauce over the fish. Put any leftover sauce in a bowl for your guests to help themselves. Serve with the boiled potatoes.