Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper or foil.
In a large mixing bowl, toss the cauliflower florets with olive oil until well coated.
Add garlic powder, smoked paprika, salt, and pepper, tossing to evenly distribute the seasonings.
Sprinkle the Parmesan cheese and breadcrumbs (if using) over the cauliflower and toss again to coat.
Spread the cauliflower in a single layer on the prepared baking sheet.
Roast in the preheated oven for 25-30 minutes, flipping halfway through, until the cauliflower is golden brown and crispy on the edges.
Remove from the oven and sprinkle with chopped parsley if desired.