Pat the steak dry with paper towels and season generously with salt and pepper. Add a splash of Worcestershire sauce if desired.

Heat the olive oil in a large skillet or Dutch oven over medium-high heat. Add the sliced onions and bell peppers and cook until softened and slightly caramelized, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant. Remove the veggies from the skillet and set aside.

In the same skillet, increase the heat to high. Add the steak in a single layer (you may need to do this in batches). Sear for about 1-2 minutes per side, until browned and cooked to your desired doneness. Remove the steak from the skillet and set aside. Let it rest for a minute or two, then slice it into bite-sized pieces.

Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions until al dente. Reserve about 1 cup of pasta water before draining.

In the same skillet, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes, until a smooth paste forms (roux). Slowly whisk in the milk, a little at a time, making sure to smooth out any lumps. Bring the mixture to a simmer, stirring constantly, until it thickens slightly, about 3-5 minutes.

Reduce the heat to low and stir in the softened cream cheese until it's completely melted and smooth. Add the provolone cheese and parmesan cheese and stir until melted and creamy. Season with nutmeg, salt, and pepper to taste.

Add the cooked pasta, sautéed veggies, and sliced steak to the cheese sauce. Toss gently to coat everything evenly. If the sauce is too thick, add a little of the reserved pasta water until it reaches your desired consistency.

Serve immediately, garnished with fresh parsley (if desired).