Cut the unpeeled aubergines into slices. Salt them, let them drain for 1 hour, then press them between 2 sheets of paper towels, and brown them in some oil.
Preheat the oven to 210°C.
Peel and chop the onion and garlic. In a casserole dish, brown them in some oil. Add the tomato pulp. Add salt and pepper and simmer for 15 minutes.
Add the beef for another 5 minutes. Place a layer of aubergine in a roaster dish, followed by a layer of meat mixture. Repeat the process, finishing with the aubergine.
Make the béchamel sauce, put it on top, add grated cheese and bake for 10 minutes. Serve hot.