Remover outer green leaves from the cauliflower and cut the head into small florets, discarding the stems (I save in freezer to make broth).
Drizzle with olive oil and sprinkle generously with salt and pepper. Toss well.
Bake for 30 minutes, tossing once, until the cauliflower is tender and starts to brown. Sprinkle with the parmesan, gruyere and parsley. Bake for 1-2 more minutes, just until the cheese melts. Season to taste and serve hot or warm. Enjoy!