Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.
In a shallow bowl, combine the Panko breadcrumbs, Parmesan cheese, grated garlic, parsley, basil, thyme, chili flakes, salt, and pepper.
Pour the melted butter into a separate bowl.
Dip each halibut fillet into the melted butter, coating both sides.
Press each fillet firmly into the breadcrumb mixture until evenly coated.
Arrange the coated fillets on the prepared baking sheet.
Drizzle any remaining butter over the fish.
Bake the Parmesan Garlic Butter Crusted Halibut for 15–20 minutes, or until the topping is golden brown and the fish flakes easily with a fork.
Finish with fresh lemon juice, extra Parmesan cheese, and flaky sea salt before serving.