In a small pot, whisk together ½ cup of mirin, ⅓ cup of sake, 3 tablespoons of sugar, and 2.5 to 3 tablespoons of miso paste. Place the pot over medium heat and bring to a gentle simmer. Stir continuously for about 3-4 minutes until the sugar dissolves completely. Once smooth, remove from heat and let it cool completely before using on salmon.

Place your fresh or thawed salmon filets in a shallow glass dish. Pour the cooled miso marinade over the salmon, ensuring each piece is well-coated. Cover the dish tightly with parchment paper or plastic wrap. Refrigerate the salmon for at least one night, or up to three days.

If you choose to cook in an air fryer, preheat it to 400°F. Remove the salmon from the marinade, allowing any excess to drip off. Arrange the filets in the air fryer basket and cook for approximately 12 minutes or until the edges are slightly caramelized and the fish flakes easily.

For baking, preheat your oven to 425°F. Place the marinated salmon on a parchment-lined baking sheet and bake for 10-12 minutes. For added flavor, broil for 1-2 minutes at the end.

Once cooked, let your Miso-Marinated Salmon rest for a couple of minutes before serving. Pair with white rice and steamed vegetables.