Cook the cheese tortellini according to package instructions until al dente.
In a large skillet, heat olive oil over medium heat.
Add the sliced flank steak to the skillet and cook until browned, about 4-5 minutes.
Stir in the sliced onions, green bell pepper, and minced garlic; cook until they begin to soften, about 3-4 minutes.
Season the mixture with salt and pepper, adjusting to your taste.
Reduce the heat to low and stir in the cooked tortellini, reserving some pasta water.
Add the shredded provolone cheese and stir until melted and creamy, adding reserved pasta water as needed.
Serve immediately, garnished with fresh herbs if desired.
