2 cups elbow macaroni noodles
4 Tb butter
4 Tb flour
1 1/4 cup milk (it helps if it's warmed slightly)
1 1/4 cups + 1/2 cup grated cheddar cheese
salt and pepper to taste
Preheat the oven to 375.
Bring a pot of water to a boil. Once boiling, salt the water and then add the noodles. Cook according to package directions.
Meanwhile make a roux by melting the butter in a saucepan over medium heat. Once melted, add in the flour, stirring to combine. Cook, stirring continually, for ~2 minutes to cook the flour.
Gradually pour in the milk, stirring to remove lumps and to prevent scorching. Once all of the milk is added, continue stirring until the sauce begins to thicken.
At that point, begin adding in ~1 1/4 cups of cheese a small handful at a time, stirring to incorporate. The cheese should melt into the liquid to make your cheese sauce. If your sauce gets a bit too thick, just add in a little more milk. Salt to taste.
Drain the macaroni once it's done, and toss with the cheese sauce. Pour the macaroni into a greased 9"x13" or 8"x8" casserole dish. Top with the remaining grated cheese.
Bake until the cheese is melted and the macaroni is bubbly (~20 min for an 8"x8" or ~12 min for the 9"x13").