Alton's Baked Mac N' Cheese

This is my favorite baked homemade mac'n'cheese recipe thus far...looks complicated, but its really easy and the leftovers are superb!

1/2lb elbow macaroni
3tbsp butter
3tbsp flour
1tbsp powdered mustard
3 cups milk
1/2 cup sweet onion, finely chopped
2 bay leaves
1/2 tsp paprika
1 large egg
12oz shredded sharp cheddar
1tsp kosher salt
fresh black pepper

Topping:
3tbsp butter
1 cup panko bread crumbs

1. Preheat oven to 350 degrees
2. In large pot of boiling, salted water, cook the pasta to al dente.
3. While the pasta is cooking, in a separate pot, melt the butter. Whisk in the flour and mustard and keep it moving for about five minutes. Make sure it is free of clumps.
4. Stir in the milk, onion, bay leaves and paprika.
5. Simmer for ten minutes and remove the bay leaves.
6. Temper in the egg. Stir in 3/4 of the cheese. Season with salt and pepper.
7. Fold the macaroni into the mix and pour into a 2qt cassarole dish. top with remaining cheese.
8. Melt the butter in a saute pan and toss the bread crumbs to coat. Top the macaroni with the bread crumbs.
9. Bake for 30 minutes!

***To temper an egg, you whisk an egg in a bowl with 1/4 cup of the hot liquid you are working with (in this case, the milk mixture). Whisk until fully blended and add into the milk mixture while continuing to stir so that the egg blends smoothly into the mixture and does not thicken up.