Cut your bread so it fits into your oven-proof soup bowl, if necessary. Toast the slices and set aside. Peel and crush your garlic clove. Peel and slice the onions. It’s okay to cry. They’ll just add flavor to the soup!
Heat the oil in a large pot over medium heat and fry the onions until they are soft. Add the sugar and keep on stirring until the onions take on a deep caramel color – this may take a while!
Stir in the garlic clove and continue to cook for about two minutes. Reduce heat to low and add the white wine. If, for some reason, you need to skip out on the alcohol you can omit the wine and replace the amount needed with water or additional broth. Wine just makes this soup ever so flavorful.
Let it all simmer for about 20 minutes, until the amount of wine is reduced in the pot and starts to become a little bit sticky. Stir in the broth and bay leaf and simmer for another 10 minutes. Add salt and pepper to taste.
In the meantime, preheat the oven to 230°C (445 °F). Ladle your soup into oven-proof soup bowls and top each with a slice of toasted bread. Sprinkle liberally with grated cheese and bake in the oven for about 10 minutes, until the cheese is melted and golden.