Quarter the potatoes. Clean, wash and slice the zucchini. Dab meat dry. Heat the oil in a pan and fry the meat well on all sides. Season with salt and pepper.
Remove from the pan and let it rest. Sauté zucchini slices in the frying fat for 2-3 minutes. Remove from the pan. Add wine and cream and bring to the boil. Add cheese and let it melt.
Bind with sauce thickener and season with salt and pepper. Fill potatoes and zucchini into two small greased gratin dishes (approx. 16 cm Ø). Cut the meat into slices and place them on the vegetables.
Pour the sauce over it and bake in a preheated oven (electric: 200 °C/ gas: level 3) for about 10 minutes. In the meantime, clean, wash, quarter and seed the tomatoes. Cut the flesh into small cubes.
Wash the chives, dab dry and cut into small rolls. Serve gratin sprinkled with tomatoes and chives.