Preheat your oven to 375°F (190°C) and butter a 2-quart baking dish. Cook the elbow macaroni according to package directions until al dente, then drain and set aside.

In a large saucepan, melt butter over medium heat. Whisk in the flour and cook for one minute, stirring constantly, to create a roux.

Gradually whisk in the milk until smooth. Bring the mixture to a simmer, stirring, then remove from heat and stir in the shredded cheddar cheese, salt, and pepper until the cheese is fully melted and the sauce is smooth.

Add the cooked macaroni to the cheese sauce and stir to combine thoroughly. Pour the mixture into the prepared baking dish.

Bake for 20-25 minutes, or until bubbling and golden brown on top. Let it cool slightly before serving.