Preheat oven to 400°F and line a baking sheet with parchment paper.
Slice the eggplant into 1/2-inch rounds, place on the baking sheet, and roast for 20 minutes until tender.
In a skillet over medium heat, brown the ground lamb with the diced onion and minced garlic until the meat is cooked through.
Drain any excess fat from the skillet, then stir in the tomato puree, oregano, cinnamon, sea salt, and black pepper.
Simmer the lamb mixture for 10 minutes to allow the flavors to meld while the eggplant finishes roasting.
In a small bowl, whisk together the Greek yogurt, egg white, and half of the parmesan cheese until smooth.
In a small oven-safe baking dish, layer half of the roasted eggplant, followed by the lamb mixture, and then the remaining eggplant.
Spread the yogurt mixture evenly over the top and sprinkle with the remaining parmesan cheese.
Bake for 20 to 25 minutes until the topping is set and develops a light golden color.