Since the "nitsuke" or simmered vermilion snapper was not a great success, I was pondering what I would do with the second fish. I thought of "papillote" (baked in parchment paper) but the fish was too big for the width of parchment paper I had. So I abandoned that idea. I could just bake or grill it but that was too mundane. So at the last moment, I used aluminum foil to make a pouch and seasoned it with miso and butter as I often cook shimeji or enoki mushrooms on the grill.
I used whatever vegetables were at hand; I used onion, shiitake mushroom, and green asparagus. I first put a long piece of aluminum foil on a large, rimmed cookie sheet (just in case juices spilled out). I made the piece long enough so that after folding it in half it would accommodate the entire length of the fish. I then made a bed of sliced onions (1 small or 1/2 large), asparagus, stem ends removed and skin peeled from the stalk, and sliced fresh shiitake mushrooms (5 large) (#1 below). I then placed the fish on top of the bed of vegetables (#2).
Miso sauce: In a small bowl, I added brown miso (4 tbs), sugar (1 tbs), mirin and sake in 1: 1 ratio until the miso reached a consistency I could smear on the skin of the fish without having it run down the sides. I also added a small amount of soy sauce for no reason. I smeared the miso concoction on the top of the fish and placed thin pats of cold unsalted butter on top (total of about 2 tbs) (#3 below).
I folded the aluminum foil in half which covered the fish and vegetables loosely leaving enough space for expansion. I crimped the two wider sides and the end to make a tightly sealed pouch and baked it in a preheated 400F convection oven for 30 minutes. After 30 minutes, some of the miso mixture was still clinging to the top of the fish but a nice sauce had developed on the bottom of the pouch with liquid coming from the vegetables and fish (#4). I gently scraped the miso from the skin of the fish and mixed it into the accumulated liquid on the bottom to further expand the sauce.
After placing the fish on a serving plate, I served the vegetables on either side of the fish (the first picture).
This turned out to be a much much better way to cook this fish than the previous method I had used (simmered or "nituske"). After my wife deboned the fish and served the meat and the vegetables on individual plates, I added a small mound of rice on the side and poured the sauce from the bottom of the aluminum foil pouch over the rice and fish.
The fish tasted much richer than it had when cooked the previous way--with sweet (not too sweet) miso flavor. We did not actually taste the butter but it definitely added to the rich flavor and texture to the fish. This was a very satisfying dish.