Preheat your oven to 350ºF. In a large skillet over medium-high heat, cook the lean ground beef until it's browned and cooked through. Drain any excess fat from the skillet, then stir in the spaghetti sauce so the meat is nicely coated. Remove from the heat and set aside for assembly later.

While the beef is cooking, boil the dried spaghetti according to package instructions. Once the pasta is al dente, drain it well and place it in a large bowl. Quickly add the softened cream cheese, Italian seasoning, and minced garlic to the hot pasta. Stir thoroughly until the cream cheese is melted and coats the noodles evenly. I recommend stirring while the pasta is still hot so the cream cheese melts smoothly.

Lightly grease a 9x13 inch baking pan. Spread a thin layer of the beef and spaghetti sauce mixture from Step 1 on the bottom of the dish. Next, gently spoon the cream cheese spaghetti (from Step 2) over the sauce, smoothing it out evenly. Top the spaghetti layer with the remaining meat sauce, ensuring it covers the noodles.

Sprinkle the grated Parmesan cheese evenly over the top of the assembled casserole. Bake in the preheated oven for about 30 minutes, or until the sauce is bubbly and the cheese has melted. I like letting the casserole rest for a few minutes before cutting—it helps to keep the layers together when serving.