1 lb elbow macaroni
1 tablespoon salt for boiling water, plus 1 teaspoon for the dish
5 tablespoons unsalted butter plus 2 tablespoons set aside for bread crumbs
6 tablespoons flour
1 1/2 teaspoons mustard powder
1/4 teaspoon cayenne pepper
4 finely chopped Jalepenos (vein and seeds removed)
5 cups whole milk
8oz Monterey Jack cheese, shredded
8oz Cheddar cheese, shredded
1 cup panko bread crumbs
Preheat oven to broil.
In a large pot or dutch oven, bring 4 quarts of water to a boil, then add macaroni noodles and 1 tablespoon salt.
Cook until noodles are tender (just past al dente).
Drain pasta and set aside.
In the same pot or dutch oven, melt 5 tablespoons butter until foaming.
Add flour, mustard, and cayenne pepper and Jalapenos. Whisk until well incorporated, about 1 minute.
Gradually whisk in the milk and bring the mixture to a boil.
Continue to whisk until mixture has thickened to about the consistency of heavy cream, then remove from heat.
Whisk in the cheeses and 1 teaspoon salt, whisking until cheese is melted.
Stir in the pasta, then cook on low, stirring often until the mixture is steaming (about 5 or 6 minutes).
Transfer the pasta mixture to a broiler-safe dish (9″x13″) and spread evenly.
Melt two tablespoons butter and mix with panko bread crumbs.
Spread the bread crumbs evenly over the pasta, and transfer the dish to the oven.
Broil for 3 to 5 minutes, or until bread crumbs brown.
Cool for 5 minutes before serving.