Brine the fish for best results. This both seasons the fish and helps keep the albumin from being released (that white exuded protein that you often find on cooked salmon). Mix 1 tablespoon of kosher salt or 1/2 tablespoon of fine grain table salt per cup of cold water. About 4-5 cups is generally enough to cover the salmon. Brine for 30 minutes at room temperature.

While the fish is brining, prepare the vegetables. Preheat the oven to 425ºF and line a rimmed baking sheet with foil. Rub some avocado oil on the foil and set aside.

Toss the radishes in a tablespoon oil and season with a bit of salt. Place face down on the line baking sheet. Bake at 425ºF for 20 minutes.

Toss the asparagus with the remaining tablespoon of oil and season with a bit of salt. Remove the baking sheet from the oven and add the asparagus. Return the pan to the oven and bake for another 10-15 minutes, or until the asparagus is tender and the radishes are beginning to brown.

While the vegetables roast, start the sauce. Combine the wine, vinegar, juice, and shallots bring to a boil. Adjust heat to medium-high and reduce the volume to about 1 tablespoon, about 10 minutes.

Strain this mixture through a fine sieve into a container and add two pieces of butter. Using an immersion blender. puree until smooth. With the blender running, continue adding butter, one piece at a time, until it is all incorporated. Adjust seasoning to taste. Keep in a warm place before serving.

Thoroughly dry the fish and season both sides with salt and pepper. Heat a cast iron skillet or oven-safe nonstick pan over high heat heat. When hot, add two tablespoons avocado oil and heat till shimmering. Add a fish filet, skin side down and press it firmly against the pan for 15 seconds with a spatula. Repeat with each piece of salmon, pressing each one to ensure contact with the pan. Continue cooking fish, pressing occasionally to maintain skin contact with the pan until you see a nicely browned crust form around the edges of the fish, roughly 5 more minutes. Do not move the fish at all and transfer to the oven and bake at 425ºF for 5 minutes, or until opaque on top and flakes easily.

To serve, spoon some sauce onto a plate, top with vegetables, top with fish, seared side up, and spoon over a bit more sauce. If you seared the fish with skin on, do not top with sauce, just divide the sauce evenly on the bottom of the two plates as it will make the skin soggy and lose its crispness.