Cook the pasta: Bring a large pot of salted water to a boil. Add the pasta and cook until just al dente according to package directions.
Reserve 1/2 cup pasta water, then drain.
Prep the steak: While the pasta cooks, place the steak in the freezer for 10 minutes to firm up. Slice very thinly across the grain. Pat dry and season with 1/2 teaspoon salt and 1/4 teaspoon pepper.
Sear the beef: Heat the olive oil in a large skillet over medium-high.
Add the beef in a single layer and cook 1–2 minutes per side until browned but still tender. Transfer to a plate. Do this in batches to avoid overcrowding.
Sauté veggies: In the same skillet, add the onion and bell peppers with a pinch of salt.
Cook over medium heat, stirring occasionally, until softened and lightly caramelized, 8–10 minutes. Add the garlic, smoked paprika, and onion powder; cook 30 seconds until fragrant.
Deglaze and build the sauce: Stir in the Worcestershire. Whisk the cornstarch into the broth until smooth, then pour it into the skillet.
Simmer 2–3 minutes, scraping up browned bits, until slightly thickened.
Add the dairy: Reduce heat to low. Stir in the Greek yogurt until creamy. Add the provolone (and Parmesan, if using) and stir until melted and smooth.
If too thick, splash in reserved pasta water a little at a time.
Combine: Return the beef and any juices to the skillet. Add the drained pasta and toss to coat. Season with remaining 1/2 teaspoon salt and 1/4 teaspoon pepper, adjusting to taste.
Finish and serve: Sprinkle with parsley.
Serve hot, adding a bit more pasta water to loosen the sauce if it tightens.