Bring a large pot of salted water to a boil. Add the elbow macaroni and cook until al dente, about 8 minutes. Drain and set aside.
In the same pot, melt the butter over medium heat. Sprinkle in the flour and whisk constantly to create a roux, about 1–2 minutes.
Gradually pour in the milk, whisking until the mixture is smooth and thickened, about 3–4 minutes.
Stir in the shredded Cheddar cheese until completely melted and glossy, forming a creamy cheese sauce.
Season with salt and pepper to taste. Remove from heat.
Return the drained macaroni to the pot and gently fold to coat every noodle in the homemade cheese sauce.
Serve immediately for gooey, cheesy perfection!