Step 1: Season the beef - Sprinkle the stew beef with salt and black pepper, giving it a good toss so every piece is seasoned. This simple step goes a long way in building flavor from the start.
Step 2: Sear the beef - Heat the olive oil in a skillet over medium high heat. Add the beef in batches and sear until browned on the outside. You are not cooking it through here, just giving it a nice crust for extra flavor.
Step 3: Transfer to the slow cooker - Move the browned beef into your slow cooker, scraping in any flavorful bits left behind in the pan.
Step 4: Add the aromatics and liquids - Add the diced onion, minced garlic, beef broth, Worcestershire sauce, and Italian seasoning to the slow cooker. Give everything a gentle stir so the beef is coated and surrounded by flavor.
Step 5: Slow cook until tender - Cover and cook on low for 4 to 5 hours, until the beef is tender and easy to pull apart with a fork. This is where the magic happens and the flavors really settle in.
Step 6: Add the cream and tortellini - Stir in the heavy cream and frozen tortellini. Gently fold everything together so the pasta is coated in the sauce.
Step 7: Finish cooking the pasta - Cover and cook for another 30 to 40 minutes, until the tortellini is tender and heated through.
Step 8: Stir in the cheese - Just before serving, stir in the shredded Parmesan cheese. Let it melt into the sauce, turning everything creamy and rich.