In 1 tablespoon of oil, saute garlic; then lightly flour pork and brown until golden. Remove pork and set aside. In same skillet, add another tablespoon of oil; saute scallions and mushrooms. Return pork to pan; sprinkle with thyme. Add 8-12 oz beer, depending on thickness of cut; bring to boil (the alcohol evaporates and leaves a "malt" flavor, so the darker the brand, the better).
Cover and simmer 8 minutes for thin, 15-20 minutes for thick. Spoon sauce over meat to serve. For a richer sauce, add 1-2 tablespoons sour cream just before serving. Serves 4.