Wash the eggplants and remove their stems. Cut them into round slices 1/2″ (1.5 cm) thick, salt them and leave in a strainer to drain out the bitter juice for 30 min. Wash with cold water and dry them.
You can fry the eggplant slices in a pan with oil until golden. I baked them on baking paper after smearing each one with oil and arranging next to one another, with the baking paper directly on the oven's cooking grid.
I put it on the highest cooking grid and turned the grill setting on to 392°F (200 °C). It took them 5 min. to bake, I flipped them over halfway through to bake on the other side. Choose whichever method you prefer.
To make the Bechamel sauce, melt the butter, add the flour, stir and braise until golden. Pour the milk in a little at a time until fully absorbed, while stirring nonstop. Season to taste, leave it to bubble and remove from the stove.
Chop the onions finely after cleaning them and braise until softened in the olive oil. Add the mince, break it apart into pieces and braise until golden.
Clean the garlic, chop it finely, add it to the onions and mince, stir and pour in the tomatoes. Next, add spices to taste and stir. Cook on moderate heat until the liquid is reduced and the dish thickens.
Smear a medium-sized tray with olive oil. Put 1/2 the eggplants at the bottom, pour on the tomato sauce and cover with the rest of the eggplants.
At the very top, pour in all of the Bechamel sauce, grate the emmental (cheese) and sprinkle with parmesan.
Put it in a preheated 392°F (200 °C) oven for 15 min. until you get a golden topping.