Bring a large pot of salted water to a boil. Add the tortellini and cook according to the package directions until just al dente. The tortellini will finish cooking in the sauce.
Drain the tortellini and set aside. Toss with a small drizzle of olive oil to keep it from sticking together.
While the water heats, season the steak with the kosher salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat until shimmering.
Add the steak in a single layer, working in batches if needed. Sear for 2 to 3 minutes without moving it, until a good crust forms. Flip and cook for about 1 minute more.
Transfer the steak to a plate. Leave the browned bits and juices in the skillet.
Reduce the heat to medium and add the butter. Once melted, add the onion and green bell pepper.
Cook for 7 to 8 minutes, stirring occasionally, until the vegetables have softened and are starting to caramelize.
Add the garlic and cook for 1 minute, stirring constantly.
Sprinkle the flour over the vegetables. Stir and cook for 1 minute, coating the vegetables evenly.
Slowly pour in the beef broth while stirring to help prevent lumps.
Add the heavy cream and Worcestershire sauce. Stir to combine.
Bring the sauce to a gentle simmer. Cook for 3 to 4 minutes, stirring occasionally, until it thickens enough to coat the back of a spoon but is still loose and pourable.
Reduce the heat to low. Add the provolone a handful at a time, stirring until melted before adding more.
Add the Parmesan and stir until melted and the sauce is smooth.
Return the steak and any accumulated juices to the skillet.
Add the cooked tortellini. Gently fold everything together until the tortellini is coated and the steak is warmed through.
If the sauce is too thick, add a small splash of beef broth or heavy cream and stir until it reaches your preferred consistency.
Sprinkle with fresh parsley and serve immediately while the sauce is creamy and the cheese is melted.