Cut 4 (12-inch-square pieces) of aluminum foil. Preheat the oven to 400 degrees F.
Working with 1 foil sheet at a time, place the foil sheets on the work surface. Place 1 1/2 cups of spinach in the center of each foil sheet. Top with a sea bass fillet. Sprinkle with 1 teaspoon of ginger and 1/2 teaspoon of garlic, then drizzle 2 tablespoons of Marsala, 2 teaspoons of soy sauce, and 1/2 teaspoon sesame oil over the fish and spinach. Gather the foil sheets over the fish. Fold in the foil edges and pinch tightly to seal. Place the foil packages on a heavy large baking sheet.
Bake until the spinach wilts and the fish is just cooked through, about 10 minutes. Transfer the packages to wide shallow bowls. Cool 5 minutes. Open package and fold down to reveal fish, being careful of hot steam. Squeeze the lime juice over the fish. Sprinkle the basil over and serve.
Recipe courtesy of Giada De Laurentiis