Gourmet Baked Macaroni and Cheese

This recipe came from the Food Network's Alton Brown, and I made a few changes based on what I had on hand. This macaroni and cheese recipe is thick and creamy, and absolutely, sinfully delectable!

Ingredients:
1/2 pound elbow macaroni
3 tablespoons butter
3 tablespoons flour
1 tablespoon powdered mustard (not yellow from the refrigerator!)
3 cups milk (preferably whole or 2%)
1/2 yellow onion, finely diced (I substituted 1/2 teaspoon onion powder)
1 bay leaf
1/2 teaspoon paprika
1 large egg
12 ounces sharp cheddar cheese, shredded
1/2 cup parmigiano reggiano cheese, shredded
1 teaspoon kosher salt (to taste)
fresh black pepper (to taste)
Topping:
3 tablespoons butter
1 cup panko bread crumbs

Directions:
Preheat oven to 350 degrees F.

In a large pot of boiling, salted water, cook the pasta al dente (6 minutes)
While the pasta is cooking, in a separate pot, melt the butter. Whisk the flour and dry mustard and keep it moving for about five minutes. Make sure it's free of lumps. Stir in the milk, onion, bay leaf, and paprika. Simmer for ten minutes and remove the bay leaf.

Temper the egg (whisk the egg in a different bowl, then slowly add small amounts of liquid from the milk flour mixture, to the egg bowl, to bring up the egg temperature until it reaches the same temp as the mixture in the pan, about a cup of liquid, then add the egg mixture to the pot). Stir in 3/4 of the cheese. Season with salt and pepper. Fold the macaroni into the mix and pour into a casserole dish. Top with remaining cheese.

Melt the butter for the topping into a saute pan and toss the bread crumbs to coat. Top the macaroni with the bread crumbs. Bake for 30 minutes. Remove from oven and rest for five minutes before serving.

Enjoy!