Chop the onions, 3 garlic cloves and sauté them.
Add the diced tomatoes, ground meat, flour, salt, pepper and herbes de provences.
When all is cooked, cut the heat and add the egg yolks and the parmesan. Mix it.
Pre-heat the oven (200ºC thermostat 6-7). Spread the hachis in a plate and spread the mashed potatoes on top of it. Dust with grated cheese and brown for 20min.