Let the salmon sit at room temperature 10-15 minutes. Preheat the oven to 375°F.
Add the salmon to a large dish or baking sheet skin side facing down. Brush the top with olive oil and season with salt and pepper.
In a saucepan, add ½ cup soy sauce, ½ cup brown sugar, 4 minced garlic cloves, 3 Tbsp lemon juice, ¼ cup salted butter, ½ tsp salt and ½ tsp ground black pepper over medium-high heat. Let simmer until the butter is melted and the sugar has dissolved, about 2-3 minutes. Stir occassionally during the process to prevent sugar from burning.
Now pour the sauce overtop of the salmon and cover the dish with foil.
Bake for 10-25 minutes (depending on size of salmon - see notes). Remove the foil and broil for the last 2-3 minutes if desired. This will help to carmelize and crispen the salmon (it's an optional step).
Add salmon to a large serving plate. Sprinkle with fresh chopped green onion if desired. Extra sauce in pan can be drizzled over rice or pasta.
Recipe Notes:
Cooking Time: The cooking time for salmon will vary depending on the thickness of the fillet. Measure the thickest part of your salmon. It will take approximately 10 minutes for every 1″ of thickness. For example, my salmon fillet was 2″ thick and took about 23 minutes to bake. This time will vary so it’s best to check on it early to avoid overcooking.Cooked salmon will be light pink and opaque (not translucent). It will also be easily flaked with a fork. Also note that the salmon will continue to cook a little bit once it's removed from the oven.