From starting to serving: 1.5 hours. Active time: 30 minutes. Serves four.
How the chefs explain it:
Thoroughly caramelise the onions, add flour and cook it out before adding stock, simmer then skim, serve with cheesy croutes.
- Add butter and olive oil and onions to a large saucepan over medium-low heat.
- Cover and cook for 15 minutes, stirring occasionally.
- Uncover, add the salt and sugar and cook over medium heat until the onions are a rich deep brown. Keep stirring!
- Add the flour, stir well and cook for 3 more minutes.
- Add the stock and wine and simmer for 30 minutes more.
- Meanwhile, thickly slice the baguette, and grate the cheese.
- Toast the baguette slices in the oven or griller, top with cheese, and toast until golden and melted.
- Skim any foam from the soup, add salt and pepper if you like and serve with croutons.