1-First Step: Get the oven and pasta ready Start by heating your oven to 375 degrees Fahrenheit. Bring a large pot of water to a boil and salt it well. Cooking the pasta in salted water matters because it seasons the noodles from the inside, which helps the final Alfredo Baked Spaghetti taste balanced instead of flat. While the water heats, lightly grease a baking dish so it is ready when the pasta and sauce come together.

2-Second Step: Cook the spaghetti until just firm Add the 1 pound of dried spaghetti noodles to the boiling water and cook them until they are just shy of al dente. This usually means taking them off the heat 1 to 2 minutes before the package says they are done. Since the pasta will bake later, keeping it slightly firm helps it stay tender instead of mushy. Drain the spaghetti well and set it aside while you make the sauce.

3-Third Step: Build the Alfredo sauce In a large saucepan over medium heat, melt the 3 tablespoons of unsalted butter. Whisk in the 3 tablespoons of all-purpose flour and cook for about 1 minute to make a smooth roux. This step helps the sauce thicken without tasting floury. Slowly pour in the 3 cups of whole or 2 percent milk, whisking constantly so the mixture stays smooth. Then add the 1 cup of heavy cream, 1/2 teaspoon of garlic powder, and 1 teaspoon of kosher salt. Keep stirring until the sauce thickens enough to coat the back of a spoon, which usually takes about 4 to 6 minutes. Lower the heat and stir in about two thirds of the mozzarella and Parmesan, saving the rest for the top. The cheeses should melt fully into the sauce, turning it glossy and creamy. If you like a slightly stronger cheese flavor, add a little extra Parmesan at this stage.

4-Fourth Step: Mix the pasta and sauce Add the drained spaghetti to the sauce and toss it until every strand is coated. Use tongs or a wide spoon so the pasta does not clump together. If the sauce seems too thick, add a splash of reserved pasta water or a little more milk. This is a handy trick for Alfredo Baked Spaghetti because the sauce should look creamy and loose before baking, not dry. The pasta should be coated, not drowned. A creamy cling is what you want before it goes into the oven.

5-Fifth Step: Assemble the bake Transfer the sauced spaghetti into the prepared baking dish and spread it out evenly. Sprinkle the remaining mozzarella and Parmesan over the top. The cheese layer is what gives you that golden, bubbly finish once the casserole bakes. If you want to add extra flavor, you can dust the top with a little more garlic powder or a pinch of black pepper.

6-Sixth Step: Bake until bubbly and golden Place the dish in the oven and bake for about 20 to 25 minutes. You are looking for bubbling edges and melted cheese on top. If you want a more golden finish, you can broil it for 1 to 2 minutes at the end, but keep a close eye on it so the cheese does not burn. This step gives Alfredo Baked Spaghetti that classic casserole look that is so inviting at the table.

7-Final Step: Rest, garnish, and serve Let the baked spaghetti rest for about 5 to 10 minutes after taking it out of the oven. This helps the sauce settle and makes serving easier. Top with finely chopped parsley leaves if you like a fresh pop of color. Then spoon it into bowls or onto plates and serve warm. It pairs well with garlic bread, a crisp green salad, or roasted vegetables if you want to round out the meal.