In a mixing bowl, combine 6 tablespoons of softened unsalted butter, 3 tablespoons of white miso paste, 1 tablespoon of brown sugar, 2 teaspoons of grated fresh ginger, and 1-2 cloves of minced garlic. Mix until smooth.

Take your salmon fillets and place them skin-side down on a lined baking tray. Spread the prepared miso butter across the surface of each fillet.

Preheat your oven to 375°F (190°C). Once heated, place the salmon in the center rack and cook for about 12-15 minutes. For caramelization, switch to broil for 1-2 minutes.

If using an air fryer, preheat to 400°F (200°C). Place the salmon fillets in the air fryer basket, ensuring they are not touching. Cook for 9-10 minutes.

Carefully transfer the cooked salmon onto a serving platter and drizzle any remaining miso butter over the top. Garnish with green onions.