Preheat your oven to 400°F (200°C).
Slice the eggplant into 1/2-inch thick rounds. Lightly brush both sides with the olive oil and place on a parchment-lined baking sheet.
Roast the eggplant for 15-20 minutes until softened and slightly browned, then remove from the oven and reduce heat to 350°F.
In a non-stick skillet over medium heat, sauté the diced onion and minced garlic until translucent.
Add the ground beef to the skillet, breaking it up with a spatula, and cook until browned. Drain any excess liquid.
Stir in the tomato puree, cinnamon, oregano, sea salt, and black pepper. Simmer on low for 10 minutes to allow the flavors to meld.
In a small bowl, whisk together the Greek yogurt, egg white, and grated parmesan until smooth.
In a small oven-safe baking dish, layer half of the roasted eggplant slices, followed by the beef mixture, and then the remaining eggplant slices.
Spread the yogurt and egg mixture evenly over the top layer of eggplant.
Bake for 20-25 minutes until the topping is set and develops a light golden-brown color.