METHOD
1. You will need a deep oven dish, ideally square, about 20 x 20cm. Brush the bottom and sides with olive oil.
2. Preheat the oven to 180C/325F/gas 4. Trim the aubergines and slice them lengthwise to 1cm thickness. Sprinkle them with salt on both sides and spread out on paper towels for at least 15 minutes. After that time pat and squeeze them lightly dry with more paper towels and brush each slice with olive oil on both sides. Place them on a baking tray (they may overlap) and bake for 20 minutes until soft and floppy.
3. Heat up 2 tbsp. olive oil in a large frying pan. Add the onions and cook for 5 minutes until softened. Add the garlic, cinnamon and oregano and cook for a couple of minutes.
4. Turn the heat up and add the ground meat. Stir it around the pan, breaking lumps with a fork, until browned and dry. Add the tomato passata and puree, the red wine and the cinnamon stick if using. Turn the heat own to simmer, cover the pan and cook for 30 minutes.
5. In the meantime slice the potatoes thinly (½ cm) and layer them at the bottom of your dish. Scoop 2 or 3 tablespoons of the meat cooking liquid and brush all over the potato slices. Place the dish under the grill for 15 minutes until the potatoes are scorched and golden.
6. Now cook the béchamel: melt the butter in a saucepan, stir in the flour and cook for a minute. Start whisking in the milk, little by little, over medium heat; it will take about 10 minutes. Stir in the double cream and season generously with salt, pepper and nutmeg. Add the cheeses, a third at a time, whisking them into the sauce. When all incorporated, check for seasoning and take off the heat.
7. Preheat the oven again (or keep it going) to 180C/325F/gas 4. Build the moussaka: spoon half the meat over the potatoes, layer half the aubergine slices, then meat again and the rest of the aubergines. Spread the béchamel over the top.
8. Bake for 45 minutes until the sauce is browned and the meat is bubbling underneath. Let it stand for 30 minutes before serving: it will be far too hot to taste it sooner and impossible to cut into squares. Serve with Greek salad, green salad or rocket. Any leftover moussaka can be briefly blasted under the grill for lunch the next day.