Long time ago, you needed just fried onions, beef broth and bread rinds to cook a French soup. Today, it is obligatory to add butter, garlic, wine and, as a rule, grated cheese. Cheese is also put on croutons, which are usually served with onion soup.
To cook 4 portions, you will need:
35.2 oz (1kg) onion
2.1 oz (60g) butter
33.8 oz (1l) beef stock
7 oz (200g) cheese
1 tsp dried thyme
4 slices French bread