Step 1

Place the miso paste, mirin, sugar, ginger, sesame oil, and salt in a small, broiler-safe baking dish just large enough to hold the salmon. Whisk until the miso is well-combined and the sugar is dissolved. Place the salmon in the marinade skin-side up. Cover and refrigerate for at least 30 minutes or up to overnight.

Step 2

Remove the salmon from the refrigerator and let it sit at room temperature while you arrange an oven rack about 6 inches from the broiling element and heat the oven to 250°F.

Step 3

Use a wide spatula to carefully flip the salmon over so it’s skin-side down in the baking dish.

Step 4

Bake until the salmon is opaque pink in the center, cooked through, and flakes easily, 25 to 35 minutes, depending on the thickness of the fillet. Check the fillet at 25 minutes by inserting the tines of a fork into the thickest part of the fillet and gently pull. If the fish is soft and flakes easily, then it is done. If it is still gooey and if the fork is difficult to pull out, bake the salmon for 5 more minutes and check again.

Step 5

Remove the salmon from the oven, turn the oven to broil, and heat for 2 to 3 minutes. Return the salmon to the the oven and broil until lightly charred in spots on the top and around the edges, 2 to 3 minutes.