Heat the oven: Preheat to 425°F (220°C). Line a large baking sheet with parchment for easy cleanup.
Slice the cauliflower: Trim leaves and the bottom stem. Slice the head into 1/2-inch rounds.
Don’t worry if some florets break off—use them as mini bites.
Season the rounds: Place rounds on the baking sheet. Brush both sides with olive oil, then sprinkle with salt, pepper, garlic powder, and onion powder.
Roast to tender-golden: Bake for 12–15 minutes, flipping halfway, until the edges are lightly browned and the centers are fork-tender but not mushy.
Pat off moisture: If you see beads of water on the rounds, blot gently with a paper towel. This helps prevent sogginess under the sauce.
Add the “pizza” layer: Spoon about 1–2 teaspoons of sauce onto each round.
Sprinkle mozzarella and a little Parmesan. Top with your chosen add-ins.
Back into the oven: Return to bake for 6–8 minutes, until the cheese melts and starts to bubble. For browned, bubbly tops, broil for 1–2 minutes, watching closely.
Finish and serve: Let cool 2–3 minutes so they set slightly.
Sprinkle fresh basil or parsley and add red pepper flakes if you like heat. Serve warm.