Alton Brown's Baked Macaroni and Cheese

1/2 lb. elbow macaroni 

3 T unsalted butter

3 T all-purpose flour

1 T powdered mustard

3 cups milk

1/2 cup onion, finely diced

1 bay leaf

1/2 t paprika

1 large egg

12 oz. sharp cheddar cheese, shredded

Freshly ground black pepper

Topping:

3 T unsalted butter

1 cup panko breadcrumbs

Preheat the oven to 350.  In a pot of boiling salted water, cook the pasta until al dente; drain.

While the pasta is cooking, in a separate pot, melt the butter.  Whisk in the flour and mustard and keep it moving for about 5 minutes.  Make sure it's free of lumps.

Stir in the milk, onion, bay leaf and paprika.  Simmer for 10 minutes; remove the bay leaf.

Temper in the egg:  Beat the egg in a small bowl with a fork; beat in a T or two of the warm sauce, then slowly whisk the egg mixture back into the sauce.  Stir in three-quarters of the cheese.  Add 1 t salt, and pepper to taste.  Fold the macaroni into the mix and pour into a 2 qt casserole dish.  Top with the remaining cheese.

Melt the butter in a sauté pan and toss in the breadcrumbs to coat.  Top the macaroni with the breadcrumbs to coat.  Top the macaroni with the breadcrumbs.  Bake for 30 minutes.  Remove from the oven and let rest for 5 minutes before serving.