Set your oven to 425°F (220°C). Place a large rimmed baking sheet inside the oven while it heats up.
Cut the cauliflower into evenly sized florets to help them roast uniformly.
In a large mixing bowl, combine the cauliflower with olive oil, garlic powder, smoked paprika, kosher salt, and freshly ground black pepper. Toss well until every piece is evenly coated.
Carefully remove the hot baking sheet from the oven. Spread the seasoned cauliflower in a single layer, leaving space between the florets to encourage browning. Avoid overcrowding the pan.
Bake for 25–30 minutes, turning the florets halfway through cooking with a spatula. Roast until the cauliflower is tender inside and golden brown around the edges.
Remove the cauliflower from the oven and sprinkle with freshly grated Parmesan cheese and chopped parsley, if desired.
Enjoy your crispy roasted cauliflower while it is hot for the best texture and flavor.