Preheat oven to 425°F (220°C). Line a large baking sheet with parchment or foil.
In a large bowl, toss cauliflower florets with olive oil, Old Bay, chili, and black pepper.
Spread the cauliflower evenly on the baking sheet, leaving space between pieces.
Roast for 25–30 minutes, flipping halfway through, until golden brown and crispy on the edges.
Sprinkle cheddar and parmesan over the roasted cauliflower. Return to oven for 5 minutes until cheese melts.
Serve immediately while hot and crispy.
