Cut the pork fillet into medallions and fry briefly in hot oil. Then pour into a baking dish.
For the sauce, cut the onions into small pieces and sauté them with a little butter until golden. Cut the leek into rings and sauté too. Then add the pizza tomatoes, crème fraiche and herbs and mix well. Season well with salt and pepper (and if you also like garlic).
Pour everything over the meat and sprinkle with the cheese.
Cook in the preheated oven for approx. 20 to 25 minutes at 220 ° C.