Preheat your oven to 400°F.
Slice the eggplant into thin rounds and lightly sprinkle with a pinch of sea salt; let sit for 10 minutes then pat dry with a paper towel.
In a medium skillet over medium heat, add the olive oil and sauté the diced yellow onion and minced garlic until soft and translucent.
Add the ground lamb to the skillet, browning it thoroughly while using a wooden spoon to break it into small crumbles.
Stir in the tomato puree, ground cinnamon, dried oregano, sea salt, and black pepper; simmer the mixture for 5 minutes to meld the flavors.
In a small mixing bowl, whisk together the Greek yogurt and the egg until the mixture is completely smooth and creamy.
In a small oven-safe baking dish, create a base layer with the eggplant slices and top with the spiced lamb mixture.
Spread the yogurt and egg custard evenly over the lamb layer to create a thick topping.
Bake for 25 to 30 minutes until the eggplant is tender and the creamy top is set and beautifully golden brown.