Peel and chop the onions. Sauté them in a pan with a generous amount of olive oil. Cut the minced meat even finer and fry it in the pan. Add the other ingredients for the minced meat sauce and cook until it thickens. Season generously.
Put the butter and wheat flour in a saucepan. Heat and stir until smooth paste but be careful not to brown them. Pour in the milk and bring to a boil stirring all the time. Remove from the heat and whisk in the grated cheese and eggs. Leave the cheese sauce to cool.
Peel and slice the potatoes. Wash the aubergines well and slice them into one centimeter discs. Preheat oven to full.
Place half of the aubergines and potatoes on the bottom of the oven proofed baking dish. The next layer will be minced meat sauce and top it with more potatoes and aubergines. Pour the cheese sauce over the whole thing.
Set the oven temperature to 160C and bake the Moussaka for at least 1 1/2 hours. Let the moussaka rest after oven for at least 15 minutes. Enjoy!