Preheat oven to 425°F and line a large baking sheet with parchment paper.
In a large bowl, toss cauliflower florets with olive oil, garlic, Italian seasoning, salt, and pepper until evenly coated.
Spread cauliflower in a single layer on the prepared baking sheet, making sure florets aren't touching.
Roast for 20 minutes, stirring once halfway through, until cauliflower is golden and tender.
Remove from oven and immediately sprinkle with Parmesan cheese, tossing while still hot so the cheese melts and adheres.
Return to oven for 3-5 minutes until cheese is golden and crispy.
Garnish with fresh parsley and serve immediately.