Preheat oven to 400 degrees. Cut cauliflower into florets and place in a single layer in an oven-proof baking pan. Toss in the garlic. Sprinkle lemon juice over cauliflower and drizzle each piece with olive oil. Sprinkle with salt and pepper.
Place casserole in oven, uncovered, for 25-30 minutes, or until the top is lightly browned. Test with a fork for desired doneness. Fork tines should be able to easily pierce the cauliflower. Remove from oven and sprinkle generously with parmesan cheese. Serve immediately.