Preheat oven to 350°F (180°C).
Make Sauce: In a large pot, heat 1 tbsp oil. Cook onion and garlic 5 mins. Add zucchini, oregano, cinnamon, honey, salt, pepper. Cook 3 mins. Add tomatoes, lentils, and 1 can of water. Simmer 30 mins until lentils are tender.
Cook Veg: Toss eggplant slices with 1 tbsp oil, roast on a tray for 20 mins. Boil potato slices for 15 mins until tender. Drain.
Assemble: In a 9x13 dish, spread sauce, then layer eggplant, then potatoes.
Make Topping: Mix ricotta, eggs, yogurt, and nutmeg. Spread over potatoes. Sprinkle with cheddar.
Bake for 20-25 mins until golden. Rest 10 mins before serving.