Prepare Oven and Pan: Position an oven rack in the upper-middle slot and preheat to 400°F (200°C). Line the heavy-duty baking sheet with parchment paper to prevent sticking.
Slice the Eggplant: Trim the ends from the eggplants. Cut the main body crosswise into twelve uniform, ½-inch thick medallions. Arrange them in a single layer on your prepared baking sheet.
Season the Medallions: In a small bowl, whisk together the avocado oil, garlic powder, red pepper flakes (if using), and a pinch of salt and pepper. Brush this seasoned oil generously over both sides of each eggplant medallion.
First Roast: Transfer the baking sheet to the preheated oven. Roast for 20–25 minutes, carefully flipping the medallions once at the halfway point. The eggplant should be tender and lightly browned.
Assemble the Bites: Remove the tray from the oven and set the oven to a high broil setting. Spoon a layer of the fire-roasted marinara onto each eggplant medallion. Combine the shredded mozzarella and grated Parmesan, then sprinkle the cheese mixture evenly over the sauce.
Broil to Finish: Return the baking sheet to the upper oven rack. Broil for 2–4 minutes, until the cheese is completely melted, bubbly, and developing golden-brown spots.
Garnish and Serve: Remove the pizza bites from the oven. Let them cool for a minute before scattering the fresh, chopped oregano over the top. Serve immediately.
