In a small bowl, whisk together the miso, tamari, vinegar, orange juice, and orange zest. Pour half into a shallow baking dish and reserve the other half.
Place the salmon in the baking dish and toss to coat. Transfer it to the fridge to marinate for two hours.
Preheat the oven to 425ºF (220ºC) and remove the salmon from the fridge. Place the sweet potato on a large baking sheet, drizzle with half the oil, and season with salt and pepper. Transfer to the oven and cook for 10 minutes.
Remove the baking sheet from the oven and make space for the salmon and broccoli. Place the salmon and broccoli on the baking sheet. Drizzle the remaining oil on the broccoli. Return to the oven and cook for 12 to 14 minutes, until everything is cooked through.
Pour the remaining miso sauce over the broccoli and salmon. Divide the salmon, broccoli, and sweet potato evenly onto plates. Garnish with cilantro and enjoy!