Cut the step of chopping cauliflower and instead roast it whole with salt and pepper.
Drizzle the olive oil all over the cauliflower and massage gently with your hands so that every part is coated. Season generously with kosher salt and black pepper if desired.
Place the cauliflower with its florets side up on a cast-iron skillet or oven-safe baking dish.
Roast for an additional hour, or until the cauliflower is tender and has a golden, slightly crispy exterior. Garnish with parsley.