01 -
Heat olive oil in a large sauté pan over medium-high heat. Add the sliced peppers, onions, and mushrooms. Sauté for about 5 minutes, or until softened.
02 -
Add the thinly sliced beef to the pan. Season with salt, pepper, and garlic powder. Sauté for 2-3 minutes, just until the beef begins to brown.
03 -
While the beef is browning, whisk together the cornstarch, beef broth, heavy cream, and Worcestershire sauce in a separate bowl until well combined. Pour the sauce into the pan and mix everything together.
04 -
Add the penne pasta to the pan and bring the mixture to a boil. Reduce the heat to medium, cover the pan, and simmer for 15 minutes, stirring periodically.
05 -
Remove the lid and stir in half of the shredded mozzarella cheese (about ½ cup). Sprinkle the remaining cheese over the top, cover the pan again, and cook for another 5 minutes, or until the cheese is melted. Serve immediately.