Preheat oven to 400°F.
Combine 8 cups cauliflower, 2 tablespoons melted butter and ¼ teaspoon each salt and pepper in a 9-by-13-inch metal baking pan; toss to coat.
Bake, flipping the cauliflower once, until browned in spots and slightly tender, about 20 minutes.
Whisk ½ cup broth, chopped garlic and the remaining 2 tablespoons butter together in a small bowl.
Carefully stir the broth mixture into the pan with the cauliflower.
Bake until the mixture is reduced by half, about 10 minutes.
Stir in 2 tablespoons Parmesan.
Sprinkle the cauliflower with 1 teaspoon thyme, ½ teaspoon oregano and ¼ teaspoon crushed red pepper.
Serve hot.