- Whisk together the miso paste, mirin, vinegar, sweet soy sauce, ginger, and sesame oil. Place the salmon filets in a baking dish, pour the marinade over the salmon, turn the filets to fully coat, cover the dish and marinate for 30 minutes or up to 8 hours.
- Position a rack 6 inches from the broiler. Preheat broiler to high. Line a broiling pan with foil and spray with cooking spray or brush with oil. Place the salmon filets on the prepared pan, brushing the tops with a layer of marinade. Discard the marinade. Broil for 6-10 minutes depending on the thickness of the filets. You can test the doneness of the filets by gently pressing down on the top of the filet with your finger or a fork. If the flesh flakes, it is done.
- Serve garnished with green onions and sesame seeds if desired.