Peel and halve the onions and slice them into thin slices. Then fry the onion slices in 50 g melted butter in a saucepan until golden yellow. Add the stock and bring to a boil. Cook the onions over medium heat for about 10-15 minutes. Pour in the wine and season with salt and pepper.
Melt the remaining butter in a large pan and toast the slices of toast until golden brown. Then lightly rub the garlic clove on the bread slices. That gives a fine garlic taste. If you don`t like garlic, you can just leave it out.
Pour the soup into 4 large fireproof soup cups. Spread the bread slices on top and sprinkle with the grated cheese. Place the soup cups on the wire rack in the preheated oven grill. The soup is ready when the cheese is lightly browned. Consume immediately so that the toast stays crispy.