Cut the meat into strips and the onions into wedges. Mix 4 tablespoons of olive oil with the gyros spice, mix with the meat, onions and a little thyme and leave to stand, covered, for at least 2 hours (preferably overnight in the refrigerator).
Heat a coated pan without fat, fry the gyros vigorously in portions. Deglaze the roasting fat with 300ml water, stir in the cream and processed cheese and bring to the boil. Season to taste with salt and pepper.
Grease a baking dish with the rest of the olive oil, add the gyros, add the sauce and bake in the preheated oven (convection oven 175 degrees) for about 30 minutes. Then take the pan out of the oven, crumble the feta, spread it on the gyros and put it in the stove for another 10 minutes to gratinate.
Rice noodles and fresh coleslaw taste best with this.