Bring a large pot of salted water to a boil. Add the rotini and cook according to package instructions. Reserve 1/4 cup of pasta water, then drain and set aside.

In a bowl, season the thinly sliced steak with salt, pepper, garlic powder, Italian seasoning, and paprika.

Heat olive oil in a large skillet over medium-high heat. Add the seasoned steak and sear for 2–3 minutes until browned. Remove the steak from the skillet and set it aside.

Reduce heat to medium and add unsalted butter to the same skillet. Once melted, sauté the minced garlic for about 30 seconds until fragrant.

Pour in the heavy cream and broth, bringing it to a gentle simmer.

Stir in the grated Parmesan (and mozzarella, if using) until the sauce is smooth, thick, and creamy.

Add the cooked spirals to the skillet, tossing gently to coat them in Alfredo sauce. Add reserved pasta water as needed to adjust the sauce's consistency.

Return the seared steak to the skillet and mix it into the creamy pasta. Let everything simmer together for 1-2 minutes to combine the flavors.

Garnish with chopped parsley, then serve hot.