Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Drain and set aside.

In a large skillet or sauté pan, heat olive oil over medium heat. Add the sliced onions and bell peppers, cooking for 5–6 minutes until softened. Stir in the minced garlic and cook for an additional 1 minute until fragrant.

Add the thinly sliced prime rib to the pan with the vegetables. Cook for 3–4 minutes until heated through and lightly browned. Season with Italian seasoning, smoked paprika, salt, and black pepper.

Reduce heat to medium-low. Sprinkle the flour over the meat and vegetable mixture, stirring constantly for 1–2 minutes to cook the raw flour taste. Gradually pour in the milk and heavy cream while whisking continuously until smooth and slightly thickened, about 3–4 minutes.

Stir in the provolone, mozzarella, and Parmesan cheese until melted and fully incorporated into a creamy sauce. Taste and adjust seasoning as needed. Add crushed red pepper flakes for a slight kick if desired.

Add the cooked pasta to the skillet, tossing gently to coat the noodles evenly with the cheese and beef mixture. Heat for 2–3 minutes to ensure everything is warmed through.

Transfer the pasta to a serving dish or individual plates. Garnish with freshly chopped parsley and additional Parmesan cheese if desired. Serve immediately while hot and cheesy.