Wash the potatoes well. Place on a baking sheet or skillet and bake in the oven until tender.
Cool and clean.
Cut into halves.
In a bowl, combine finely chopped onion, mayonnaise and grated cheese. Salt to taste.
Place the filling over the potatoes.
Bake in the oven for another 10-12 minutes at a temperature of 200 degrees C.
Put on a platter and garnish with vegetables and herbs.