Ingredients:
1/2 lb elbow macaroni
3 tablespoon butter
3 tablespoon flour
1 tablespoon powdered mustard
3 cups milk
1/2 cup yellow onion, finely diced
1 bay leaf
1/2 teaspoon paprika
1 large egg
12 ounce sharp cheddar, shredded (low fat can be used)
1 teaspoon kosher salt
Fresh black pepper
Topping:
3 tablespoons butter
1 cup panko bread crumbs

Directions:
Preheat oven to 350 degrees.
In large pot of boiling, cook pasta to al dente.
While the pasta is cooking, in a separate pot, melt 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 ten minutes and remove the bay leaf.
Temper in the egg. Stir in 3/4 of the cheese. Season with salt and pepper. Fold the macaroni into the mix and pour into a 2 quart casserole dish. Top with remaining cheese.
Melt the butter in 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.