Wash the potatoes and cook in salted water for about 20 minutes. Quench briefly, peel and let cool off. In the meantime wash, clean and slice the tomatoes. Clean and wash spring onions and cut them into rings.
Wash the rosemary, pluck the needles. Cut the potatoes into slices and put them mixed with tomatoes and spring onions on a greased baking tray (30 x 32 cm). Sprinkle with salt, pepper and rosemary needles.
Put bay leaves in between. Coarsely grate the cheese and sprinkle over it. Bake in the preheated oven (electric range: 200 ° C / gas: level 3) for 25-30 minutes.