Unwrap your fish and pat it dry.
In a shallow pan, combine the marinade ingredients.
Stir together the miso, mirin, rice wine vinegar, sugar and garlic and whisk until smooth.
Place the fish in the mixture and turn to coat.
Cover the pan and return it to the fridge to marinate for 30 minutes or more.
Preheat your Traeger to 400*.
When the grill is hot, remove the fish from the marinate and place it directly on a parchment lined cookie sheet.
Insert the Meater Thermometer in the thickest part of the fish.
Pair the thermometer with the app and set to a target temperature of 128*.
Place the cookie sheet in the grill and close the lid.
Allow the fish to cook about 20 minutes or until the Meater app alerts you to a target finish temperature.
Remove your roasted miso marinated black cod from the Traeger and serve immediately with simple Asian-inspired sides.