Cook the onion in extra virgin olive oil till slightly browned.
Stir in the minced meat, season with salt and pepper, oregano and cinnamon.
Cook for a couple of minutes, pour in the polpa and set to simmer for 20 minutes.
Meanwhile slice the aubergines and grill.
Peel and slice the potatoes thinly and boil with the rosemary.
Prepare a bechamel sauce; melt the butter in a sauce pan, stir in the flour and cook into a white roux. Pour in the milk gradually, stirring continuously on medium heat, simmer into a thick white sauce. Season with salt and pepper, stir in the grated parmesan cheese, remove from heat, beat in yolks.
Line an oven proof dish with grilled aubergines, top up with potatoes, cover with the meat sauce. Repeat with the remaining ingredients. Cover with the bechamel sauce. Sprinkle with extra cheese and bake for 20 minutes, till golden brown.