Elevate the standard French dip to ‘The Dipper.’ Sliced roast beef is cooked together with mushrooms, hot peppers, onions, and Marsala wine, then piled into toasted buns topped with Swiss cheese.
Preheat oven to 500 degrees F (260 degrees C).
Heat olive oil in a large pot or Dutch oven over medium heat. Cook and stir onion, 1 tablespoon garlic basil spread, and Italian seasoning in the hot oil until onion has softened, 4 to 5 minutes. Stir in pepper rings and mushrooms; cook and stir until mushrooms have softened, about 5 minutes.
Pour in Marsala wine and bring to a boil, scraping up any browned bits from the bottom of the pan. Add beef broth and roast beef and stir until the beef is warmed through, 3 to 4 minutes.
Spread each ciabatta roll with 1 tablespoon garlic basil spread and 1 tablespoon horseradish sauce. Top with 3 slices Swiss cheese.
Place sandwiches on a baking sheet and bake in the preheated oven until the cheese is melted and the bread is toasted, 3 to 4 minutes. Using a slotted spoon, pile the beef-onion mixture into each sandwich and pour 1 to 2 tablespoons pan juices over the filling. Transfer the remaining pan juices to small bowls for dipping.
Per Serving: 976 calories; protein 55.5g; carbohydrates 123.1g; fat 28.4g; cholesterol 93.7mg; sodium 2723mg.