Preheat the oven to 450 degrees F. Line a large, rimmed baking sheet with foil and spray it with olive oil.
Slice the eggplant crosswise into ½-inch-thick rounds, yielding about 12 rounds. Place the eggplant rounds on the prepared baking sheet. Spray them with olive oil spray. Sprinkle with kosher salt, black pepper, and garlic powder.
Bake the eggplant rounds for 10 minutes. Remove from the oven, turn them over, spray with more olive oil, and bake for 10 more minutes.
Remove the pan from the oven but leave the oven on. With a spoon, spread marinara sauce on each eggplant round. Top with shredded cheese. You can add more toppings at this point, such as pepperoni or olives.
Return the pan to the oven. Bake just until the cheese is melted, about 5 minutes. Let rest for 5 minutes before serving.
Video
Notes
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently, in the microwave on 50% power.They are surprisingly good cold, by the way. If you like leftover cold pizza, I think you will like leftover cold eggplant pizza!