Preheat your oven to 400°F and line a baking sheet with parchment paper.
Slice the eggplant into 1/2-inch rounds and lightly brush with the olive oil.
Roast eggplant for 15 minutes until tender and set aside.
In a skillet over medium heat, brown the ground lamb with the diced onion and minced garlic.
Stir in tomato puree, cinnamon, oregano, sea salt, and black pepper, simmering for 10 minutes until the sauce has thickened.
In a small bowl, whisk together the Greek yogurt and egg until completely smooth.
Layer half the eggplant in a small baking dish, top with the lamb mixture, then the remaining eggplant slices.
Pour the yogurt mixture over the top layer and sprinkle with parmesan cheese.
Bake for 20 to 25 minutes until the topping is firm and beautifully browned.