In a large pot of boiling salted water, cook the cheese tortellini according to package instructions. Drain and set aside.
In a large skillet, heat 1 tablespoon of olive oil over medium-high heat. Season the sliced steak with salt and pepper. Add the steak to the skillet and sear for about 2-3 minutes or until browned. Remove the steak from the skillet and set aside.
In the same skillet, add the remaining tablespoon of olive oil. Add the sliced onion, and cook for about 3 minutes until softened. Then, add the garlic, red bell pepper, and mushrooms. Sauté for another 5-7 minutes until the vegetables are tender.
Return the seared steak to the skillet alongside the cooked tortellini. Sprinkle in the Italian seasoning and toss everything together. Cook for an additional 2-3 minutes to heat through.
Sprinkle the shredded mozzarella cheese evenly over the skillet mixture. Cover the skillet with a lid and reduce heat to low. Allow the cheese to melt for about 3-4 minutes.
Once the cheese is melted and bubbly, remove from heat and garnish with fresh parsley.
Notes
Feel free to add more vegetables or adjust seasoning to taste.