Step 1

Peel and trim 1 1/2 pounds carrots. If they are more than 1-inch thick, cut them in half lengthwise; otherwise, leave them whole. Cut the carrots crosswise into 2-inch-long pieces. Thinly slice 4 medium scallions, keeping the white and green parts separate. Pat 4 salmon fillets dry with paper towels, then season on both sides with 1 teaspoon of the kosher salt and 1/4 teaspoon of the black pepper.

Step 2

Heat 2 tablespoons of the olive oil in a large nonstick skillet with a lid over medium-high heat until shimmering. Add the salmon skin-side up and sear until golden-brown on the bottom, about 4 minutes.

Step 3

Transfer the salmon skin-side down to a plate (it will not be cooked through). Add the remaining 2 tablespoons olive oil to the pan. Add the carrots and scallion whites, and season with the remaining 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper. Sauté until the carrots are crisp-tender, about 5 minutes. Meanwhile, stir 2 tablespoons Dijon mustard and 1 tablespoon honey together in a small bowl.

Step 4

Reduce the heat to medium. Return the salmon skin-side down to the pan, nestling it among the carrots. Spread the honey mustard onto the salmon with the back of the spoon. Cover and cook the salmon to desired doneness, 2 to 5 minutes depending on the thickness of the fillets. An instant-read thermometer inserted into the middle of the thickest fillet should register 120°F to 130°F for medium-rare or 135°F to 145°F if you prefer it more well-done. Sprinkle with the scallion greens.