Melt the butter in a pot and add the onions. Salt the onions immediately and cook over low heat for at least 40 minutes until they are soft and browned.
Add a tablespoon of flour and let it cook for about two minutes.
Pour in the liter of beef broth and cook for another half hour.
Place a slice of toasted white bread on top of the soup and sprinkle with grated cheese.
Cooks by profession and passion. Has taken the web by storm with scrumptious recipes cooked to the rhythm of music and ASMR. Impossible to resist his videos: a triumph of sounds and crunchiness.