ingredients

• 12  ounces  dried campanelle or penne pasta
• 1  17-ounce package  refrigerated cooked beef roast au jus
• 2  large  fresh portobello mushrooms, stems removed and coarsely chopped (about 4 cups)
• 1  medium  sweet onion, cut into thin wedges
• 2  cloves  garlic, minced
• 2  tablespoons  butter
• 3  tablespoons  all-purpose flour
• 2  tablespoons  tomato paste
• 1  14-ounce can  beef broth
• 1  tablespoon  Worcestershire sauce
• 1  teaspoon  smoked paprika or Spanish paprika
• 1/4  teaspoon  salt
• 1/4  teaspoon  ground black pepper
• 1  8-ounce carton  sour cream
• 1  tablespoon  prepared horseradish
• 1  teaspoon  snipped fresh dill or 1/4 teaspoon dried dill
•     Fresh dill sprigs (optional)