500 g onions
1 tbsp flour
300 ml white wine
8 thin slices of rye bread
8 thin slices of Gruyère cheese
Roast the slices of bread in the oven until they are quite crispy. Place two slices of bread and two slices of cheese alternately in each of four soup cups (complete with cheese).
Cut the onions into half rings and roast in butter until light brown. Dust with flour and deglaze with white wine. Add 600 ml of water, season with salt and pepper. Boil and pour into the soup bowls.
Cook in preheated oven at 200-220 degrees for about 20-30 minutes until cheese is well melted.
In neighboring canton of Vaud white bread is used instead of rye bread. In some regional recipes, the onions are first precooked in milk.