Add lentils to a large saucepan of salted water and bring water to a boil. Cook lentils at a bare simmer until tender, about 15 to 20 minutes. In a blender or food processor grind oats into meal. Drain lentils in a sieve and in a bowl combine with garlic, coriander, cumin, and 3 tablespoons ground oats. Mash lentils coarse with a potato masher. Stir in egg and salt and pepper to taste and form mixture into six 3-inch burgers, each 1/2-inch thick. Coat burgers with remaining ground oats and chill, uncovered, 15 minutes. In a small bowl stir together yogurt, mint, and salt and pepper to taste. In a large skillet heat 1/4 inch oil over moderately high heat until hot but no smoking and fry burgers, in batches if necessary, until browned and crisp, about 3 to 4 minutes on each side. Serve burgers in pitas with lettuce and yogurt mint sauce. Yield: 6 servings NOTES : (Courtesy of Gourmet Magazine) Recipe by: Cooking Live Show #CL8825 Posted to MC-Recipe Digest V1 #492 by Angele Freeman on Mar 2, 1997.