Bring a large pot of salted water to a rolling boil over high heat. Add the penne pasta and cook it according to package instructions until al dente, typically about 8-10 minutes. Once cooked, drain the pasta in a colander, reserving 1 cup of the pasta water for later use. Set the penne aside.

While the pasta cooks, season your sirloin or ribeye steak tips generously with Cajun seasoning, garlic powder, smoked paprika, salt, and black pepper. In a large skillet, heat 2 tablespoons of olive oil over medium-high heat. Sear the steak for 3-4 minutes per side until they're beautifully browned and medium-rare. Transfer the steak tips to a plate and keep warm.

Using the same skillet, reduce the heat to medium and add 2 tablespoons of butter. Once melted, sauté minced garlic for about 30 seconds until fragrant. Gradually pour in 1 cup of heavy cream and ½ cup of whole milk, stirring constantly. Then, add 4 ounces of cream cheese and mix until melted and smooth.

Continue to stir the creamy sauce over medium heat, adding 1 cup of freshly grated Parmesan cheese and 1 cup of mozzarella cheese until fully melted. If the sauce appears too thick, incorporate the reserved pasta water until you reach your desired consistency.

Gently toss the drained penne into the skillet with the sauce, followed by the seared steak tips. Cook for an additional 2-3 minutes over low heat until everything is heated through. Finally, garnish with fresh parsley and serve immediately.