01 - Preheat the oven to 400°F. Lightly grease a baking dish large enough to hold the halibut fillets in a single layer.
02 - Pat the halibut fillets dry with paper towels. Brush both sides with olive oil and season generously with salt and pepper.
03 - Arrange the seasoned fillets in the prepared baking dish.
04 - In a small bowl, whisk together the melted butter, lemon juice, lemon zest, minced garlic, and chopped parsley until well combined.
05 - Pour the lemon butter sauce evenly over the halibut fillets, ensuring each piece is coated.
06 - Bake for 15-20 minutes, or until the fish flakes easily with a fork and is opaque throughout. The exact time will depend on the thickness of the fillets.
07 - Transfer the baked halibut to plates. Spoon any remaining sauce from the baking dish over the top. Garnish with lemon slices and additional parsley if desired.
08 - Serve immediately while hot.