Preheat oven to 300F
Using a butter knife or the back of a stiff knife, place fish on flat surface and scale by pushing the knife against the grain. The scales should fly off the fish and may be a bit muddy. Rinse well under cold water.
Clean the fish by pressing down on the side of the fish, make a slit along the belly and remove the soft innards and discard.
Lay the sablefish onto a parchment laid baking sheet.
In a small bowl, mix the miso paste, mirin and sake or white wine.
Using a brush, generously brush the miso mixture into the cavity in the fish.
Generously brush the miso mixture onto the exterior skin of the fish.
Place fish into oven and bake for 20-30 minutes or until internal temperature reaches 135F.
Remove from oven and serve immediately with salt and pepper, lemon and japanese mayonnaise. (It can be difficult to move onto a serving platter if the sablefish is large. This was >5lbs) Serving on baking sheet is not pretty, but functional.
