Cook the Tortellini: Bring a large pot of salted water to a rolling boil. Add the cheese tortellini and cook according to package instructions, typically 3-5 minutes until al dente. Drain and toss with 1 tablespoon of olive oil to prevent sticking.

Sear the Steak Bites: Season steak bites with salt, black pepper, and garlic powder. Heat 1 tablespoon of olive oil in a skillet over medium-high heat. Add steak bites in a single layer and sear for 2-3 minutes on each side until browned. Remove and set aside.

Make the Creamy Sauce: In the same skillet, reduce heat and add unsalted butter. Once melted, add minced garlic and sauté for about 1 minute. Pour in heavy cream and broth, stirring well. Simmer for 2-3 minutes, then whisk in Parmesan and Italian seasoning until smooth.

Add Spinach and Sun-Dried Tomatoes: Stir in fresh spinach to wilt it into the sauce. Add sun-dried tomatoes if using. Cook for an additional 1-2 minutes until spinach is wilted and sauce is creamy.

Combine Tortellini and Steak: Return drained tortellini and seared steak to the skillet with the creamy sauce. Toss gently until coated and heated through.

Serve: Transfer to a serving dish or bowls. Garnish with chopped parsley and additional Parmesan cheese. Serve immediately.