Step 1

Whisk miso, sugar, mirin, sake, soy sauce, and oil together in medium bowl. Pat cod dry with paper towels and place in 1-gallon zipper-lock bag. Pour miso mixture over cod. Press out air, seal bag, and turn to coat cod in marinade. Refrigerate for at least 8 hours or up to 24 hours, turning occasionally.

Step 2

Adjust oven rack 8 inches from broiler and heat broiler. Set wire rack in rimmed baking sheet and line with aluminum foil. Lightly spray foil with vegetable oil spray. Wipe excess marinade from cod with your fingers, leaving thin layer on cod, and transfer to prepared wire rack, skin side down.

Step 3

Broil until cod is deeply browned and registers 125 degrees, 8 to 12 minutes, rotating sheet halfway through broiling and shielding fillets with foil if they begin to get too dark. Serve with pickled ginger.