Slice the beef thin: For easier slicing, chill the beef in the freezer for 20–30 minutes.
Slice against the grain into thin strips. This keeps it tender.
Sauté the aromatics (optional but recommended): In a skillet over medium heat, melt butter. Add onions and peppers and cook 5–7 minutes until softened and lightly browned.
Add mushrooms and cook 3 minutes more. Stir in garlic for 30 seconds. Transfer everything to the crockpot.
Layer the beef: Add sliced beef on top of the veggies in the crockpot.
Add seasonings and broth: Sprinkle in salt, pepper, onion powder, and Italian seasoning.
Pour in beef broth and Worcestershire. Stir gently to combine.
Slow cook: Cover and cook on Low for 6–7 hours or on High for 3–4 hours, until the beef is very tender.
Stir in the creamy elements: Switch to Low (or keep on Low if already there). Add cream cheese cubes and heavy cream.
Stir until the cream cheese melts and the broth turns creamy, about 10–15 minutes.
Add the provolone: Stir in provolone in batches until melted and smooth. Taste and adjust salt and pepper.
Serve: Ladle into bowls and garnish with chopped parsley. For extra cheesesteak vibes, top with an additional slice of provolone and let it melt on top.