Wash the thyme, shake dry and grate the leaves from the stalks. Wash and clean the tomato and cut into thin slices. Wash and clean the zucchini, cut in half lengthwise and cut into slices.
Heat the oil, add the zucchini and fry for about 4 minutes, turning. Stir in sour cream and season to taste with salt, pepper and lemon juice. Add thyme, except for something to garnish. In the meantime, bring salted water to the boil in a wide saucepan.
Add the pasta, bring to the boil and simmer for about 5 minutes. Remove carefully with a skimmer and rinse immediately in cold water. Halve the ham. Fill each noodle plate half with ham, zucchini and tomato.
Overlap the noodle plates. Finely chop the toast in the universal chopper. Place sandwiches on a baking tray lined with baking paper. Mix parmesan, bread and thyme and spread evenly on the sandwiches.
Drizzle with butter. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-15 minutes.