Remove the outer green leaves from the cauliflower and cut the head into florets, discarding the stems. Place the florets on a sheet pan. 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 and Gruyere and bake for 1 to 2 more minutes, just until the cheese melts. Season to taste and serve hot or warm.
When taping this episode, Ina garnished the dish with chopped parsley before serving.
This recipe has been updated and may differ from what was originally published or broadcast.