Marinate the cod
Combine the sugar and water in a small pan and bring to a boil. Cool and stir in the miso, mirin and sake. Cut the black cod into four equal pieces, about 3 oz. each. Coat the cod in the miso glaze and marinate overnight (at least four hours).

Prepare the spinach rolls
Blanch the cabbage leaves in salted, boiling water until softened and remove to a clean cutting board. Lay the leaves flat and trim the thickest part of the rib off. Blot the leaves dry and reserve. Heat the oil in a large sauce pan then add the garlic and shallots. Saute just for aroma then add the spinach and stir quickly. Cook until the spinach becomes completely soft, seasoning with salt and pepper, then remove and allow to cool. After the spinach has cooled, press all liquid from the leaves. Divide in half and roll each roll into a 1" diameter cylinder and wrap in the blanched cabbage leaves. Rub the leaves lightly with olive oil and roll in the sesame seeds to coat. Reserve until ready to serve. ( It is sometimes helpful to wrap the rolls in plastic wrap).

Make the soy lime vinaigrette and assemble the dish
Combine all ingredients for the vinaigrette in a small bowl and mix well. Season to taste with salt and pepper. Toss the spinach leaves in a small amount of the vinaigrette and arrange four of five leaves along the rim of each plate. Slice the spinach rolls into six slices each and arrange three slices next to the spinach on each plate. Place the marinated cod on a baking pan and broil for 5 to 7 minutes until the surface becomes lightly browned and the fish is fully cooked. Place the fish in the center of each plate and serve.