Preheat oven to 450°F. Combine butter and Basil Pesto Sauce in a small bowl and set aside.
Add onions and tomatoes to a medium bowl with Natural Grapeseed Oil and lemon zest; toss to combine. Season with salt and pepper if desired.
Cut eight 12-inch sheets of foil and arrange 4 flat on the counter. Divide onion and tomato mixture among foil sheets, mounding in the center of each
Pour 1 tablespoon of wine over the mixture. Place one fillet on top of each vegetable mound and spread a quarter of the pesto butter on top of each fillet
Place a second square of foil on top of the fish and crimp edges together to create a packet. Place packets on a sheet pan, overlapping slightly if necessary
Bake packets for 10 minutes until fish is cooked through 140F. Carefully open foil, allowing steam to escape away from you. Using a thin metal spatula, gently slide fish onto a plate and place vegetables back into the oven, uncovered, for 10 minutes until tender. Serve immediately.
