01 -
Melt butter in a large pot over medium heat. Add diced onions, green bell peppers, and mushrooms. Cook until onions are translucent.
02 -
Stir in chopped roast beef and minced garlic. Cook for 2-3 minutes until the garlic is fragrant.
03 -
Add flour to the pot, stir well, and cook for 3 minutes.
04 -
Gradually add beef broth while stirring continuously. Add half and half, Worcestershire sauce, salt, and pepper.
05 -
Bring the soup to a boil, then reduce heat and simmer for 10 minutes, stirring occasionally.
06 -
Mix water and cornstarch in a bowl until dissolved. Return the soup to a boil, add the cornstarch slurry, and stir for 3 minutes to thicken.
07 -
Remove from heat and stir in shredded provolone until melted. Garnish with chopped parsley and extra cheese, if desired.