Cook the 8 ounces elbow macaroni in a large pot of boiling, salted water until al dente. Approximately 10 minutes.
In a separate pot, make a roux by melting the 2.5 tablespoons butter and whisking in the 2.5 tablespoons all-purpose flour and 1 tablespoon ground mustard. Cook the mixture for approximately five minutes until it begins to darken.
Whisk in the 2 ½ cups of whole milk, 1 bay leaf, ½ teaspoon onion powder, ½ teaspoon garlic powder, and ½ teaspoon paprika. Simmer for ten minutes until the milk begins to thicken and coat the back of a spoon. Remove the bay leaf.
Temper in the 1 large egg and 1 egg yolk. To temper the egg mixture, scramble the egg and egg yolk in a small glass measuring cup. Slowly pour in ⅓ of the milk mixture while whisking constantly. Pour the egg and milk mixture back into the pot.
Add the 8 ounces provel cheese and season with 1 teaspoon kosher salt and ¼ teaspoon freshly ground black pepper. Stir until the cheese has melted. Taste and adjust seasoning if necessary.
Fold the macaroni into the milk mixture and pour into a 2-quart casserole dish.
Make the bread crumb topping by melting the 3 tablespoons butter in a saute pan and stirring in the 1 cup panko bread crumbs. Sautee until the bread crumbs begin to brown.
Top the macaroni and cheese with the bread crumbs. Bake for 30 minutes. Remove from the oven and rest for five minutes and top with 2 tablespoons fresh parsley before serving.
Notes
Making It Ahead of TimeLike most baked pasta dishes, macaroni and cheese is great for making ahead of time. Here are a few tips:
The sauce can be made ahead and stored, covered in the refrigerator, for two days. Warm the sauce while you cook the pasta. Then toss the sauce and pasta together and bake according to the directions in the recipe below.
You can also prepare the macaroni and cheese through step seven and store it, covered in the refrigerator, for three to five days. Cold macaroni and cheese may take a little longer than 30 minutes in the oven to be fully heated and cooked through.
How to Store and Reheat LeftoversStore leftovers in an air-tight container in the refrigerator for three to five days. To reheat place on a microwave-safe dish and microwave on high for one to two minutes.Tips
If you can't find Provel cheese, substitute four ounces of shredded white cheddar, two ounces of shredded Swiss, and two ounces of shredded provolone, along with two tablespoons of cream cheese for extra creaminess, and 1 teaspoon of liquid smoke.
When cooking your pasta you want to undercook it slightly. I usually reduce the recommended cooking time on the package by two minutes. The pasta will finish cooking in the oven. Once your pasta is done cooking, drain and rinse it to stop the cooking process.
Watch the sauce carefully. Simmering dairy can boil over quickly!