For the lamb toast au gratin, salt and pepper the lamb medallions and brush with the pressed garlic.
Heat the olive oil in a pan and sear the medallions on both sides. Then remove the medallions from the pan, drain on kitchen paper and sprinkle with thyme.
Cut the onions into rings and sauté in the frying oil until translucent. Slice the tomatoes and olives.
Brush a baking dish with oil, place the slices of toast in it, top with tomatoes and olives. Place the lamb medallions, the onion rings and finally the raclette cheese slices on top.
Bake in the preheated oven at 180 degrees for about 15 minutes and serve the baked lamb toast hot.