This is my homemade version of this New Mexico favorite, and I thank my sister for the idea of using soy sauce. If you want to skip all the cooking and do a bit of driving instead (see Driving 580 Miles for a Burger on Beez's blog), you could just go to the Owl Cafe in San Antonio, New Mexico for one of the world's best Green Chile Cheeseburgers. Be sure to follow the recommendation in the restaurant review (click on the Owl Cafe link given here) and go up the road afterwards for some homemade fudge for dessert. My family heartily recommends the Chocolate Coconut Fudge.
Savory Hamburger Buns (made with or without the oregano, marjoram, or basil)--you may substitute store-bought hamburger buns if you must
The best ground round you can get
Fresh ground black pepper
Fresh green New Mexico chile, peeled, seeded, and chopped (if you are silly enough to live somewhere else than New Mexico, you can order fresh chile from Hatch Chile Express in August of any year, and prepare it like this).
Slices of Monterey Jack cheese
Mix the soy sauce and black pepper with the meat. Shape the meat into patties about 1/3 lb. each. Grill over an open fire. When almost done, top with a generous amount of green chile and a slice of cheese. Grill further until the cheese melts.
Lightly toast the split hamburger buns. Assemble the burgers with chopped lettuce, sliced tomato, and a slice of sweet onion, if you wish. Eat them outside on a summer day on a covered patio.