How to Make It
Heat oven to 425° F. On a large rimmed baking sheet, toss the potatoes and broccoli with 2 tablespoons of the oil, ½ teaspoon salt, and ¼ teaspoon black pepper. Roast, tossing once, until the vegetables are tender, 25 to 30 minutes.
Meanwhile, in a small bowl, whisk together the miso, vinegar, 1 tablespoon of the remaining oil, and 3 tablespoons water.
Heat the remaining teaspoon of oil in a large nonstick skillet over medium-high heat. Season the salmon with ¼ teaspoon each salt and black pepper and cook until opaque throughout, 3 to 4 minutes per side. Drizzle with the sauce, sprinkle with the crushed red pepper, and serve with the vegetables.