Slice the beef as thinly as possible against the grain. Pat dry with paper towels. Finely chop the onion and mince the garlic.

Heat olive oil in a large, deep skillet over medium heat. Add the chopped onion and cook for 4-5 minutes until soft and translucent. Add the minced garlic and cook for 1 more minute, stirring constantly.

Increase heat to medium-high. Add the sliced beef in a single layer. Season with salt and black pepper. Let cook undisturbed for 2-3 minutes to develop a sear, then stir and cook for another 2-4 minutes until browned. Transfer beef to a plate using a slotted spoon, leaving onions and garlic in the pan.

Pour beef broth into the skillet, scraping the bottom with a wooden spoon to release browned bits. Bring to a simmer for about 1 minute. Reduce heat to medium-low and slowly stir in the heavy cream. Bring to a gentle simmer.

Reduce heat to low. Add shredded provolone cheese gradually, about half a cup at a time, stirring constantly after each addition until fully melted. The sauce should be smooth and glossy.

Return the browned beef and any accumulated juices to the skillet. Add the tortellini directly to the sauce. Cook for 3-4 minutes for fresh tortellini or 4-5 minutes for frozen, stirring gently, until tortellini is tender and floating. The sauce will thicken as the tortellini cooks.

Taste and adjust seasoning with additional salt and pepper if needed. If sauce is too thick, add a splash of beef broth to loosen. Garnish with chopped fresh parsley and serve immediately.