1. Cook the cheese tortellini by boiling a large pot of salted water and following the package instructions. Drain and set aside.
2. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat and sear the thinly sliced beef until browned and just cooked through. Remove the beef and set it aside on a plate.
3. Add another tablespoon of olive oil to the same skillet and sauté the sliced green bell pepper, onion, and minced garlic over medium heat. Cook until soft and slightly caramelized, about 5–7 minutes, then season with salt and pepper.
4. Melt 2 tablespoons of butter in the same skillet on medium heat, add the all-purpose flour, and whisk to create a roux. Cook for about 1–2 minutes until the flour is lightly golden.
5. Slowly whisk in the whole milk or heavy cream, stirring continuously to avoid lumps. Let it thicken, then add the shredded provolone cheese and stir until fully melted. Add salt and pepper to taste.
6. Return the cooked beef and sautéed vegetables to the skillet, mixing them into the creamy provolone sauce.
7. Gently combine the cooked tortellini with the sauce, beef, and vegetables, ensuring everything is evenly coated.
8. Optional: Transfer everything to a baking dish, sprinkle with extra provolone cheese, and broil for a few minutes until bubbly and golden.
9. Garnish with freshly chopped parsley before serving.