Preheat your oven to 400°F and line a baking sheet with parchment paper.
Slice the eggplant into 0.5-inch thick rounds, brush both sides with olive oil, and roast for 15 minutes until softened.
While the eggplant roasts, brown the ground lamb in a skillet over medium heat with the diced onion and minced garlic.
Stir in the tomato puree, ground cinnamon, sea salt, and black pepper, then simmer for 5 minutes until the sauce has thickened.
In a small bowl, whisk together the Greek yogurt, egg white, and parmesan cheese until the mixture is smooth.
In a small oven-safe baking dish, layer half of the roasted eggplant rounds, top with the lamb mixture, and then the remaining eggplant.
Spread the yogurt custard evenly over the top layer and bake for 20 minutes until the topping is golden and bubbly.