Slice the beef thinly. Cut peppers and onions into strips. Slice mushrooms. Mince the garlic.
Season beef with salt, pepper, paprika, and Italian seasoning. Toss to coat evenly.
Add onions, peppers, mushrooms, and garlic to the slow cooker. Pour in broth and Worcestershire.
Nestle the seasoned beef into the cooker and stir. Cover and cook on High 4 hours or Low 6–7.
About 20 minutes before serving, boil pasta in salted water until al dente. Drain well.
Stir the cream cheese into the slow cooker until melted and the sauce is smooth.
Fold in the cooked pasta. Sprinkle provolone and mozzarella over the top.
Cover and heat 10–15 minutes on High, until cheese is melted and bubbly.
Finish with parsley. Spoon into bowls and serve hot.