An hour before using, take the salmon fillets outside the refrigerator and allow to come to room temperature.
Preheat the oven to the 210°C, air circulation, rack in the middle.
We start with the Couscous by placing a medium saucepan over medium heat and a minute later adding 1 tbsp of the oil. When it heats up add the onion and sauté for 5-6 minutes, until soft and translucent. Add the broth, turn up the heat and bring to a boil. Add the couscous, reduce the heat to minimum, stir and simmer for 10 minutes with the lid on. Turn the heat off and cover with a kitchen towel and with the lid on. Let stand for 10 more minutes. Take a fork and gently fluff the couscous and stir the pine nuts and the mint. Season to taste.
In the meantime, take a small oven-proof rectangular dish and brush the remaining oil. Pat dry your salmon fillets and place them in the oven dish skin side down and baste with the Miso sauce. Cover the dish with foil and cook for total 20 minutes. 5 minutes before the end uncover and finish the cooking.
Remove from the oven, serve in a plate where the couscous is placed and optionally drizzle some Mint Oil around the dish.