Preheat oven to 400°F. Cut cauliflower into florets and put in a single layer in an oven-proof baking dish. Toss in the garlic. Sprinkle lemon juice over cauliflower and drizzle each piece with olive oil. Sprinkle with salt and pepper. If the oven hasn't reached 400°F yet, set aside until it has.
Place casserole in the hot oven, uncovered, for 25-30 minutes, or until the top is lightly brown. Test with a fork for desired doneness. Fork tines should be able to easily pierce the cauliflower. Remove from oven and sprinkle generously with grated cheese. Serve immediately.