Preheat your oven to 350ºF. Bring a large pot of salted water to a boil. Add the thin spaghetti noodles and cook according to the package directions until al dente. Drain and set aside. Meanwhile, lightly spray a 9x13-inch pan with cooking spray and set it aside for assembly.

In a large bowl, whisk together the eggs, grated parmesan cheese, and melted unsalted butter. Add the drained spaghetti noodles from Step 1 and toss until the noodles are well coated with the egg, cheese, and butter mixture. Transfer the coated noodles to the prepared 9x13-inch pan, spreading them evenly.

In a medium bowl, combine softened cream cheese, sour cream, Italian herb blend, and minced garlic. Mix until smooth and creamy. Spread this mixture evenly over the pasta in the baking dish. I like to let the cream cheese soften at room temperature for about 30 minutes before mixing, as it blends much more easily.

In another bowl, combine the cooked Italian sausage or ground beef and the jarred spaghetti sauce. Mix well to evenly distribute the meat throughout the sauce. Spread this meat sauce over the cream cheese layer in the pan, ensuring it covers the entire surface.

Sprinkle the shredded mozzarella evenly over the top of the meat sauce layer. Place the baking dish in the preheated oven and bake for 45 minutes, or until the cheese is melted, bubbly, and lightly golden. For a little extra color, you can broil the top for the last 2-3 minutes. I find that letting the baked spaghetti cool for about 5 minutes before serving helps it set and makes it easier to cut into portions.