Peel and cut the potatoes and eggplants into round shapes. Cut the zucchini first into two halves and then in slices. 

Fry everything in the evening and leave them overnight in a strainer so that the oil drains.The following day, sauté the onion in the olive oil, then add the mince, after that, the sauce, parsley, dill, the stock cube, salt and pepper. Let it boil for 15 minutes.

To make the béchamel, put the margarine and the vegetable oil in a pot to brown, add the flour and whisk. About a minute later, add the milk, salt and pepper. 

Take a 30x40 baking tray and start the layers, beginning with the potatoes.

Arrange the potatoes next to one another and if you have more, use them to fill in the empty spaces. 

Then, layer the zucchinis and on top of them, the mince, sprinkling 250 g feta cheese on top. 

Cover the mince and the feta cheese with a layer of eggplants then another layer of mince and the rest 250 g of the feta cheese.

Slowly pour the  béchamel over the top and sprinkle with the 150 g of Gouda.

Bake in a convection oven at 150°C, for 1 hour.