Preheat the oven to 375℉.
In a large saucepan bring 2-3 quarts of water to a rolling boil and add a pinch of salt. Add 3 cups of short tubular pasta and cook for about 12-15 minutes or until just past al dente. Drain pasta, reserving at least 1½ cup of the pasta water.
Melt 4 tablespoons of butter in a large sauté pan with high sides.
Once the butter has melted, whisk in the all-purpose flour and salt, keeping everything moving until a roux forms and begins to darken to a light amber.
To the roux add 2-3 tablespoons of pasta water, one tablespoon at a time, until it is smooth, velvety, and slightly thin.
Add 1 cup of the shredded cheese into the sauté pan with the roux, stirring to combine. Once fully incorporated, stir in another 1 cup of shredded cheese.
Once all the cheese is melted, add the whipping cream and additional pasta water, if necessary, to get the sauce to a smooth but slightly runny consistency.
Add the hatch chiles to the cheese sauce and stir well to combine.
To the cheese sauce add the cooked and drained pasta and stir to get it evenly coated with the cheese.
In a lightly-greased casserole dish, place the macaroni and cheese in an even layer.
In a small skillet melt the remaining 2 tablespoons of butter. Add the granulated garlic and allow it to dissolve then add the panko breadcrumbs. Stir the breadcrumbs until they begin to turn a light golden color then remove the from the heat.
Evenly top the macaroni and cheese with the toasted panko and the remaining ½ cup shredded cheese.
Back uncovered for 10-12 minutes, or until the topping has turned a deep golden brown and the cheese sauce is bubbling around the edges.
Allow macaroni and cheese to sit for at least 5-7 minutes before serving.