Rip off 4 pieces of parchment to form packets each about 12-inches long. Season fish with salt and pepper. Place a piece of parchment in a shallow dish then in the center of the paper stack 1/4 of the scallions and shiitakes, layer with slices of ginger and garlic and top with fish.
Combine the honey, vinegar and tamari and pour 1/4 of the sauce over fish. Fold over the top of the parchment then roll the sides in to form a sealed pouch. Repeat with remaining parchment and ingredients.
Arrange the pouches on a baking sheet and roast in hot oven 12 to 14 minutes.
Rachael (b/c by now, we're on a first name basis) puts a Lemon Chive Noodle with this, which I've never made. I just cook up some thin spaghetti whole wheat noodles and dump the packet of fish, shrooms and juices on top of it. All the juices from the pack works perfectly for a sauce. Amazing. Plain and Simple.