Bring a large pot of salted water to a boil. Add the elbow macaroni and cook according to the package directions until al dente. Drain the noodles and set them aside for later use.

While the noodles are cooking, melt the unsalted butter in a small saucepan over medium heat. Add the all-purpose flour and whisk it together with the butter, forming a roux. It is normal if there are a few flour lumps at this stage.

Gradually pour the whole milk into the roux, whisking continuously to combine. Continue whisking until the flour dissolves completely and the mixture is smooth and thickened, about 2-3 minutes. Add the shredded sharp cheddar cheese and whisk until the cheese melts and the sauce is thick and creamy. I find that patience during this step gives you the smoothest, creamiest sauce.

Pour the finished cheese sauce over the cooked elbow macaroni (from Step 1) in a large bowl or directly in the pot. Stir thoroughly until all the noodles are coated with the cheesy sauce. Scoop into serving bowls or prepare for baking.

Preheat your oven to 350°F (175°C). Transfer the cheesy noodles from Step 4 into a baking dish. For extra cheesiness, sprinkle additional shredded cheddar cheese on top if you have any left. Bake for 15 minutes, or until the cheese on top is melted and bubbly. I like to let it cool just a few minutes before serving so you get the gooey, creamy texture.