Prepare a grill and light the fire. Rub 1 side of each shingle with 1/2 teaspoon of oil.
Season the fish on both sides with Essence. Place a fillet on each oiled shingle. Place the shingles in the center of a hot barbecue grill. Close the lid and cook for about 10 minutes, or until the fish flakes easily with a fork. Remove the shingles from the grill using a long-handled spatula. If the shingles catch fire, sprinkle with a little water.
Put the shingles in the center of large plates. Spoon the garlic spinach on the side, and drizzle the fish with the wine reduction sauce.
Yield: 4 servings