Cook one pound of pasta (small shells, rotini, or elbows work best) according to package directions.
Meanwhile, melt a stick of butter (4 ounces or eight tablespoons) in a one-quart pot over medium heat.
Add one teaspoon salt and ½ teaspoon black pepper.
Whisk in ½ cup unbleached white flour.
Cook for a minute, whisking constantly.
Slowing pour in one quart of cream or half & half or whole milk (depending on how extravagant you are feeling), whisking constantly until the texture becomes thin.
Continue cooking and whisking every thirty seconds or so, being sure to catch the bottom of the pot, until the sauce becomes thickened.
Remove from the heat.
In a large casserole dish, apply a thin layer of the sauce to the bottom of the pan.
Layer then with 1/3 of the pasta, 1/3 of the remaining sauce, and ½ a pound of shredded sharp cheddar cheese.
Repeat with the remaining pasta, sauce and cheese.
On the top layer, use the remaining cheese to form a final layer that covers all the pasta completely.
Bake at 375 for thirty minutes or until the top is very well browned and bubbly.
