Ingredients  : 

1/4 cup sugar
2 tablespoons mirin (sweet Japanese rice wine)
2 tablespoons white miso (fermented soybean paste)
2 6-ounce skin-on black sea bass or branzino fillets, pin bones
removed
1 1/2 tablespoons vegetable oil, divided
Kosher salt, freshly ground pepper
4 cups mixed salad greens
1 tablespoon balsamic vinegar
Ingredient info: Mirin and white miso are available at some
supermarkets.

Direction   : 

In a medium-sized bowl, mix together the mirin, miso and sugar
until well-combined. Put in the fish and turn until well-coated.

Cover the bowl and keep it in the fridge for a minimum 12 hours
and to a maximum of 1 day while turning the fish in the marinade
mixture from time to time.

In a medium-sized non-stick skillet, put 1 tablespoon of oil and
let it heat up over medium heat setting. Take the marinated fish
out of the marinade mixture and scrape off any of the excess;
sprinkle it with pepper and salt to taste. Put the marinated fish the
skin side facing down and let it cook for about 4 minutes until it
has caramelized and turned dark brown in color. Flip the fish over
and allow it to cook for about 3 more minutes until it just
becomes opaque in the middle.

In the meantime, put the remaining 1/2 tablespoons of oil in a
medium-sized skillet and let it heat up over medium-high heat
setting. Put in the greens and allow it to cook for about 1 minute
while mixing it just until the greens have wilted. Add pepper and
salt to taste then distribute among each of the plates.

In the same skillet, put the vinegar and let it cook for about 30
seconds while stirring it continuously until it is thick in
consistency.

Drizzle the reduced vinegar on top of the greens then put the fish on top.