Preheat oven to 400°F (200°C). Line a large sheet pan with parchment paper or lightly oil it.
In a small bowl, whisk together the miso paste, rice vinegar, lemon juice, ginger, garlic, and sesame oil.
1 tbsp miso paste, 1 tbsp rice vinegar, 1 tbsp lemon juice, 1 tsp ginger, 1 clove garlic, 1 tsp sesame oil
Toss sweet potato cubes with half the olive oil, garlic powder, and black pepper. Spread them on the sheet pan and roast for 10 minutes first.
1 sweet potato, 1 tbsp olive oil, ½ tsp garlic powder, ¼ tsp pepper
While sweet potatoes start roasting, brush the salmon fillets generously with the miso ginger glaze.
2 4 oz salmon fillets
Toss broccolini in the remaining olive oil and a little more pepper.
1 cup broccolini
After 10 minutes, remove the sheet pan from the oven. Push sweet potatoes to one side and add the salmon fillets and broccolini.
Roast everything together for another 15-18 minutes, or until the salmon flakes easily (internal temp 125-130°F for medium) and the broccolini are tender-crisp.
Sprinkle toasted sesame seeds and sliced green onions over the salmon and veggies.
1 tsp sesame seeds, 2 green onions