Preheat your oven to 375°F (190°C). This temperature is perfect for baking fish, ensuring it cooks evenly and stays moist.
In a food processor, combine the pitted Castelvetrano olives, large basil leaves, extra virgin olive oil, capers, minced garlic, and lemon zest. Pulse until the mixture is finely chopped and well combined. You want a spreadable consistency, so add more olive oil if necessary to achieve the desired texture.
Place the whitefish filets in a baking dish. Season them generously with freshly ground black pepper. The fish should be arranged in a single layer for even cooking.
Using a spatula, spread the basil tapenade evenly over the top of each fish filet. Make sure each piece is well-coated to absorb all the delicious flavors during baking.
Place the baking dish in the preheated oven and bake for about 15-20 minutes, or until the fish is opaque and flakes easily with a fork. Cooking time may vary slightly depending on the thickness of the filets.
Once the fish is done, remove it from the oven and let it rest for a few minutes. Serve with fresh lemon wedges on the side for an added zing. Enjoy your Basil Tapenade Baked Whitefish with a simple salad or your favorite grain for a complete meal.