1-First Step: Heat the oven and get the pasta water ready

Preheat your oven to 375°F so it is ready when the pasta and sauce are mixed. Bring a large pot of salted water to a boil. The extra salt in the water helps season the spaghetti from the inside out, which makes the final dish taste fuller and more balanced.

Add 1 pound of dried spaghetti noodles and cook them for 1 minute less than al dente. This part matters because the pasta will keep cooking in the oven. If you boil it too long now, the Alfredo Baked Spaghetti can turn soft later.

2-Second Step: Make the creamy sauce base

While the pasta cooks, place a pot over medium heat and melt 3 tablespoons unsalted butter. Once the butter is melted, whisk in 3 tablespoons all-purpose flour. Keep whisking until the mixture looks golden and smells a little nutty. That step cooks out the raw flour taste and helps the sauce thicken properly.

Slowly whisk in 3 cups whole or 2 percent milk and 1 cup heavy cream. Add the liquid a little at a time so the sauce stays smooth. Bring it to a boil, then lower the heat and simmer until it thickens enough to coat a spoon. For a lighter version, you can use 2 percent milk and a bit less cream, though the sauce will be slightly less rich.

3-Third Step: Add the cheese and seasoning

Remove the pot from the heat before adding the cheese. Stir in 4 ounces of the shredded mozzarella and 3 ounces of the Parmesan, along with 1/2 teaspoon garlic powder and 1 teaspoon kosher salt. Whisk until the cheese melts into a silky sauce.

This is where the Alfredo flavor really comes through. The mozzarella gives stretch and creaminess, while the Parmesan adds salty depth. If you want to read more about the ingredients that give garlic its punch, here is a useful external resource on the health benefits of garlic.

4-Fourth Step: Combine the spaghetti and sauce

Drain the cooked spaghetti well, then add it straight into the cheese sauce. Toss until every strand is coated. If the sauce seems very thick, you can loosen it with a small splash of reserved pasta water, but only add a little at a time.

This Alfredo Baked Spaghetti works best when the noodles are evenly coated but not swimming in sauce. You want enough creaminess to bake beautifully without ending up soupy.

5-Fifth Step: Assemble the baking dish

Transfer the coated spaghetti to a baking dish and spread it out in an even layer. Sprinkle the remaining mozzarella and the remaining Parmesan on top. This top layer is what turns golden and bubbly in the oven.

If you are making the dish for a crowd, you can assemble it a little ahead of time and hold it in the fridge before baking. That makes it a good option for busy nights, potlucks, and holiday meals.

6-Sixth Step: Bake until bubbly and golden

Bake the Alfredo Baked Spaghetti for about 20 minutes at 375°F. The cheese should melt through and the sauce should bubble around the edges. If you want a deeper browned top, switch the oven to broil for 3 to 4 minutes. Stay close during this part because cheese can brown fast.

This step gives the dish its cozy baked finish. The pasta underneath stays tender, while the top gets just enough color for that homemade casserole look.

7-Final Step: Rest, garnish, and serve

Let the baked spaghetti cool for 5 minutes before serving. This short rest helps the sauce settle, so the slices hold together a little better on the plate. If you like a fresh finish, sprinkle finely chopped parsley leaves on top.

Serve it warm and creamy right away. It pairs nicely with a simple salad, roasted vegetables, or garlic bread if you want to make dinner feel complete.