Preheat your oven to 400 degrees F and grease a 9-inch x 13-inch baking dish with 1 tablespoon of butter. Set aside.
Bring a large pot of salted water to a boil. Cook the macaroni according to the package directions until al dente. Drain the water using a colander and set aside.
Place the same large pot over medium heat. Add the remaining 2 tablespoons of butter to the pot, and once melted, whisk in the flour to form a roux. Cook for 1-2 minutes, stirring frequently. Whisk in the half and half until smooth. Simmer until the white sauce has thickened, and then remove from the heat.
In a medium mixing bowl, whisk the egg yolks. Then, add one spoonful of the white sauce to the yolks while whisking quickly. (Tempering will keep the eggs from scrambling when added to the sauce.) Repeat the process two more times until the egg yolks are warmed. Slowly pour the egg yolk mixture back into the white sauce while whisking. Stir until well combined.
Add the cumin, jack cheese, half of the cheddar, and the green chiles to the sauce. Stir to combine - the cheese does not need to be fully melted. Add the cooked pasta to the pot and stir to coat.
Pour the mac and cheese into the prepared baking dish and spread into an even layer. Then sprinkle the remaining cheddar cheese over top of the pasta.
Bake for 10 minutes. Then turn your oven to broil and cook until the top starts to bubble and become golden, about 5 minutes.