Why is it that Hatch chiles are in season when it is least convenient to cook them? The peppers, which are harvested in August and September in the Hatch Valley of southern New Mexico, benefit from a long, slow cooking process that infuses a dish with their pervasive tingle. They’re great in chilis, enchilada sauces, and baked macaroni and cheese.When Hatch chiles start to hit grocery stores around early August—bringing such delicacies as Hatch-chile yogurt and Hatch-chile chocolate chip cookies to Central Market—cooking those hearty meals is a bit . . . unattractive. You can freeze roasted Hatch chiles very easily, but if you don’t want to wait for cooler weather, I’ve got you with this speedy stovetop mac and cheese.Processed cheese—you know, the stuff that gives queso its…