Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.
In a food processor, pulse the cauliflower florets until they resemble rice grains. Transfer to a microwave-safe bowl and microwave on high for 5-7 minutes, until soft. Let cool.
Once cool, wrap the cauliflower in a clean kitchen towel and squeeze out as much moisture as possible.
In a mixing bowl, combine the riced cauliflower, shredded mozzarella, grated Parmesan, beaten egg, oregano, garlic powder, salt, and pepper. Mix until well combined.
Transfer the cauliflower mixture to the prepared baking sheet and shape it into a pizza crust, about 1/4 inch thick.
Bake in the preheated oven for 15-20 minutes, or until the crust is golden brown and firm.
Remove the crust from the oven and spread marinara sauce evenly over the base.
Layer the fresh mozzarella slices on top of the sauce and return the pizza to the oven for another 10 minutes or until the cheese is melted and bubbly.
Once out of the oven, top the pizza with fresh basil leaves and drizzle lightly with olive oil.
Allow to cool slightly, slice, and serve warm.
Notes
Serve the pizza on a wooden cutting board for a rustic touch, and scatter a few extra basil leaves around the edges for an appetizing look.