Begin by bringing a large pot of salted water to a boil. Add the fettuccine or linguine and cook according to the package instructions until al dente, usually around 8-10 minutes. Once cooked, reserve about 1 cup of the pasta water, then drain the pasta and set it aside.
In a large skillet, heat the butter and olive oil over medium heat. Once the butter has melted, add the shrimp to the skillet. Cook for 2-3 minutes on each side, or until the shrimp are pink and opaque. Remove the shrimp from the skillet and set them aside.
In the same skillet, add the sliced green onions and minced garlic. Sauté for about 1 minute until fragrant. Be careful not to burn the garlic! Sprinkle the flour over the mixture and stir for another minute to cook off the raw flour taste.
Gradually whisk in the milk, ensuring there are no lumps. Bring the mixture to a simmer, then add the cream cheese cubes. Stir continuously until the cream cheese has melted and the sauce is creamy.
Stir in the seasoned salt and pepper, adjusting to taste. The sauce should be rich and flavorful, so feel free to add more seasoning if desired.
Add the drained pasta to the sauce along with the cooked shrimp. Toss everything together until the pasta is well coated in the creamy sauce. If the sauce is too thick, gradually add some of the reserved pasta water until you reach the desired consistency.
Remove the skillet from the heat and stir in the shredded mozzarella and freshly grated Parmesan cheese. Mix until the cheeses are melted and evenly distributed throughout the pasta.
Serve your Cheesy Garlic Shrimp Alfredo hot, garnished with additional green onions or cheese if desired. This dish is best enjoyed fresh but can also be enjoyed as leftovers!
