Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish. Bring a large pot of lightly salted water to a boil, then cook the spaghetti, stirring occasionally, until it is tender but still firm to the bite, about 12 minutes.

While the pasta cooks, heat a skillet over medium-high heat and brown the ground beef, breaking it up as it cooks, for 5 to 7 minutes. Drain the fat, then stir in the spaghetti sauce. Drain the cooked spaghetti and transfer it to a large bowl.

Add the cream cheese, minced garlic, Italian seasoning, and garlic salt, stirring until the cream cheese melts and the spaghetti is evenly coated.

Spread a small layer of the meat sauce in the bottom of the prepared baking dish, then layer the spaghetti on top, followed by the remaining meat sauce. Sprinkle the Parmesan and mozzarella cheeses evenly over the casserole.

Bake in the preheated oven until the dish is bubbly and the cheese is melted, about 30 minutes.