- 1 tablespoon butter
- 1/2 onion, thinly sliced
- 2 cups beef broth
- 1 1/2 teaspoons dry sherry
- 1 teaspoon Worcestershire sauce
- 1 pinch ground thyme
- 1 pinch dried rosemary
- 1 pinch dried parsley
- 2 tablespoons grated Parmesan cheese
- 2 rolls
- Melt butter in a 2-quart saucepan over medium heat; add onion, cook and stir until clear and soft, 2 to 3 minutes. Add broth, sherry, Worcestershire sauce, thyme, rosemary, and parsley to the onions; stir to combine. Bring to a boil, reduce heat and simmer for 1 hour.
- Set oven rack about 6 inches from the heat source and preheat the oven's broiler. Cut rolls in half and broil until toasted, 2 to 3 minutes.
- Ladle soup into two mugs, sprinkle with Parmesan cheese. Serve rolls on the side.