Peel skin off onions. Slice onions into rings. Separate rings and put in frying pan.
Add 100 grams of butter to frying pan.
Cook onion on medium heat until glazed (i.e. onion becomes soft). Gently turn onion periodically to avoid burning.
Add bottle of wine and the bouillon.
Simmer for half an hour. - During this time:
grate the cheese if it is not already grated, and
pre-heat the oven to 180 degrees Celsius
Ladle (or spoon) the onion and wine into the bowls.
Sprinkle the cheese over the top of each bowl.
Put the bowls in the oven for 20 minutes. When the cheese is fully melted, it is ready to serve (some people prefer to wait until the cheese has cooked to a golden brown).
Side dish: baguette (the traditional French bread stick)
The choice of cheese depends on personal preference. Generally a hard white cheese is used. In France you could use a Compte, in England you could use a Cheddar. However, feel free to experiment with different cheeses for variety and to find the taste you and friends/family most enjoy.