01 - Preheat the oven to 400°F (200°C). Line a baking dish with parchment paper or grease lightly.
02 - In a small bowl, whisk together olive oil, lemon juice, lemon zest, minced garlic, thyme, salt, and black pepper.
03 - Pat halibut fillets dry with paper towels and place them in the prepared baking dish.
04 - Brush marinade evenly over fillets and top each with a couple of lemon slices.
05 - Bake for 15–18 minutes, or until the fish turns opaque and flakes easily with a fork.
06 - Remove from oven, sprinkle with chopped parsley, and serve immediately.