In a large pot or Dutch oven, heat a splash of olive oil. Brown the lamb in batches.
Remove from the pot and set aside. In the same pot, fry the onion, garlic, bay leaf and cinnamon until soft and fragrant.
Add the lamb back into the pot then add the tomatoes, tomato paste and red wine. Season with salt and pepper. Reduce the heat and allow to simmer for 30 minutes.
Slice the eggplant and potatoes into ½cm slices. Place in a single layer on sheet pans.
Drizzle with olive oil and season with salt then roast for 20 minutes until cooked and golden brown. Remove from the oven.
Place a layer of potatoes in the bottom of a 32cm/12.5in baking dish. Add half of the eggplant then add all of the meat sauce.
Top with the remaining eggplant, the bechamel sauce and a generous handful of Parmesan.
Place in the oven and allow to bake for 45-60 minutes until golden brown and bubbling.
Remove from the oven and allow to rest for 10 minutes before slicing and serving.