Making the soup:
- In a large skillet or soup pot on low/medium heat, melt the butter and olive oil, then add the onions and sugar, and cook until soft and caramelized (don’t burn them). Stir often. Mine took about 30 minutes.
- Once the onions are caramelized, add the broth, water, wine, Dijon mustard, thyme and bay leaf.
- Bring to a boil on high heat, then reduce the heat to medium and gently simmer, covered for about 20 minutes.
Preparing the cheese/bread topping:
- Set your oven to the broil setting.
- While the soup is simmering, you can prepare the cheese and bread that make the topping.
- Shred the cheese. Set aside.
- Cut the baguette into 1/2 inch slices, and butter each side. Place them on a baking sheet.
- Put the bread slices in your preheated oven to toast, about 2 minutes per side. Careful not to burn them, you really just want them to be toasty like croutons!
- Once they are toasted, remove the toasts from the oven, and cut them into chunks that are just a little bigger than bite sized. Set aside.
Putting it all together:
- Once the soup has cooked for its 20-30 minutes, remove the thyme and the bay leaf.
- Ladle the soup into individual oven safe bowls. This recipe filled 4 bowls very generously, or you can spread them out between 6 small portions.
- Add the bread chunks to the top of the soup, being generous to cover the top.
- Sprinkle on the Swiss and parmesan cheeses.
- Sometimes I like to garnish the soups with a little sprig of fresh thyme.
- Line the bowls up on a cookie sheet, and put them in the oven under the broiler until the cheese is melted, bubbly and slightly browned, don’t burn them! This takes about 3 minutes.
- Enjoy!