If there's a basic toolkit for Mexican cooking, it contains basic red chile and green chile recipes. This one is about as simple as it gets for a chile verde. You could substitute a medium sized tomato for the tomatillos if you like (don't bother roasting them beforehand as you would the tomatillos) - different but acceptable for gringos.
1 lb. pork shoulder cut into 1-inch cubes
4 green chiles, peeled and chopped
long green chiles, not Serrano.
2 cloves garlic, crushed
1 medium onion, chopped
1 cup boiling water
Salt & Pepper
Peel the papery husks from the tomatillos, wash them and stem them and cut them into quarters. Heat a comal or heavy skillet on medium-high heat and place the tomatillos on the fully heated surface. Cook tomatillos pieces all all sides until each side gets black spots on them. Be careful not to cook so long that they get too squishy to remove with tongs. Take out of skillet and place aside.
Sauté pork in oil until well browned. Drain off all but 1 tablespoon of oil/fat. Heat again and add chopped chiles, garlic, onion cooking for about 1 minute. Add tomatillo pieces and water, season with salt and pepper to taste. Cover tightly and simmer 1 hour.