Heat the oven to 350 degrees.
Melt the one tablespoon of butter in a small fry pan. Add Panko bread crumbs and cook until toasted. Stirring often. About 5 minutes. Add some chopped cilantro if you'd like for extra flavor. Remove from heat and set aside.
In a 7 quart oven safe Dutch oven, cook macaroni according to package directions for al dente . Drain, reserving ¼ cup of the pasta water.
In the same Dutch oven, heat the stick of butter over medium heat until melted, then stir in the flour. Stir until the mixture is blended and smooth, about 1-2 minutes.
Remove from the heat and slowly whisk in the milk. Add the dry mustard, white pepper, Chamayo chile powder, and salt. Return to heat and stir until mixture begins to simmer. Reduce the heat to low and simmer for 3 minutes, stirring occasionally, until starting to thicken.
Stir in the cheese until blended and smooth. Stir in the chopped chile peppers , tomatoes and the cooked elbow macaroni and stir until macaroni is well coated. Drizzle half and half and reserved pasta water around the edges of the casserole, no need to stir.
Cover the Hatch chile mac and cheese and bake 20 minutes. Remove the lid, add the toasted Panko bread crumbs and bake uncovered an additional 10 minutes.