For the potato pancakes stuffed with cheese, peel the potatoes and grate finely. Put them in a kitchen towel and squeeze them well to get a dry potato mass.
Chop or grate the onion and add to the potato mixture together with the egg, season with nutmeg and salt. Bake a small test pancake in a frying pan with clarified butter. If necessary, mix a little more potato starch into the mixture.
Cut the cheese into thumb-length and 2 cm wide pieces and cover with the potato mixture. Bake the potato and cheese pancakes in a frying pan with clarified butter until done.
Mix well the vinegar, oil and mustard and season well with salt and freshly ground pepper. Dress the cleaned leaf salad with the sauce and bring to the table with the potato and cheese pancakes.