In a large mixing bowl, combine the cauliflower florets with olive oil, minced garlic, onion powder, smoked paprika, salt, and black pepper. Toss well to ensure all florets are evenly coated.
Spread the cauliflower mixture in a single layer on a baking sheet lined with parchment paper.
Roast in the preheated oven for about 25-30 minutes, stirring halfway through, until the cauliflower is tender and golden brown.
Remove the baking sheet from the oven and sprinkle the grated Parmesan cheese over the hot cauliflower. Return to the oven and roast for an additional 5 minutes, or until the cheese is melted and bubbling.
Once roasted, remove from the oven and let it cool slightly. Garnish with fresh parsley before serving.