Preheat the oven to 425˚F. Line a rimmed baking sheet with parchment paper.
Place the cauliflower florets in a medium-large bowl and toss with the extra-virgin olive oil.
In a small bowl, combine the garlic powder, onion powder, salt, smoked paprika, and freshly ground black pepper.
Add the spice mixture to the cauliflower and toss until the cauliflower is evenly coated.
Place the cauliflower florets, evenly spaced, on the parchment-lined baking sheet.
Roast for 25 to 30 minutes, rotating the pan halfway through, until the cauliflower edges are browning. Serve while hot and garnish with chopped fresh parsley, if desired.
Notes
The roasting time will slightly vary depending on the size of the cauliflower florets and your oven. If the cauliflower florets are smaller, check them at 15-20 minutes.
Make sure the cauliflower florets are dry (with a clean kitchen towel) before tossing them with olive oil and spices to get the caramelized edges.
Give the cauliflower florets some space and leave room between them so they roast rather than steam.
If doubling the recipe (using 1 large head cauliflower), use 2 baking sheets. Dry the cauliflower florets in a towel before seasoning. Roast for 30 to 35 minutes, rotating the pans halfway through, until the cauliflower edges are browning.
Note the spice and salt amounts are for a large cauliflower. If your cauliflower is smaller, adjust the seasoning accordingly.