Cut the feta cheese into pieces and fry with the minced meat. In the meantime, fry the zucchini and tomato in slices. When the cheese has melted and the minced meat is well seared, stir in the ketchup and spices (I`ve also used spicy sauce instead of ketchup). Then layer everything like a `normal` lasagna in a baking dish (minced meat, zucchini, tomatoes, lasagne platters). As many layers as can fit in the baking dish. The last layer should be ground beef. Spread the creme fraiche on top and sprinkle with cheese. Bake the whole thing in the oven for about 45 minutes at 180 ° C.