Optional sear for extra flavor: Heat olive oil in a large skillet over medium-high heat. Quickly brown the beef in batches, 1–2 minutes per side for shaved steak or 4–5 minutes for ground beef.
Don’t cook through—just get color. Transfer to the slow cooker.
Load the veggies: Add sliced onions, bell peppers, mushrooms, and garlic to the slow cooker. Sprinkle in salt, pepper, paprika, and Italian seasoning.
Add liquids: Pour in beef broth and Worcestershire sauce.
Stir gently to distribute seasoning and nestle the beef among the vegetables.
Cook low and slow: Cover and cook on Low for 5–6 hours or on High for 2.5–3 hours, until the beef is tender and the vegetables are soft but not mushy.
Make it creamy: Stir in the softened cream cheese. Cover and let it melt for 10–15 minutes, then whisk or stir until smooth and combined.
Add the cheeses: Stir in shredded provolone or mozzarella and the Parmesan. Taste and adjust seasoning with more salt and pepper if needed.
Cook the tortellini: About 10–15 minutes before serving, add the refrigerated tortellini directly to the slow cooker.
Stir, cover, and cook on High for 10–15 minutes, just until the tortellini are tender. If using frozen tortellini, add 5–10 extra minutes.
Finish and serve: Stir everything gently to coat the pasta in the sauce. Top with fresh parsley or chives and extra Parmesan.
Serve hot.