- 60 g butter
- 2 tbsp olive oil
- 480 g onions, sliced
- 3 cans beef broth
- 120 ml Marsala wine
- 1 tsp dried thyme
- 2 tbsp sugar
- Salt and pepper, to taste
- 2 bags croutons
- 40 g Parmesan cheese, grated
- 2 slices Swiss cheese, diced
- 8 slices provolone cheese
1. Melt butter together with olive oil in a large pan over medium heat.
2. Add onions and stir until translucent.
3. Add beef broth, Marsala wine and thyme. Simmer for 30 minutes.
4. Add sugar and season with salt and pepper—be careful not to over-salt.
5. Ladle soup into oven-safe bowls and place a handful of croutons in each. Sprinkle parmesan and Swiss cheese and layer 2 slices of provolone cheese on top.
6. Place bowls on a cookie sheet and boil in the preheated oven until cheese bubbles and browns.