Place oil in a 5 to 6 quart pan with meat and onions. Saute, stirring frequently. Add garlic powder, oregano, paprika, cumin, salt and tomato sauce. Chop the whole tomatoes into large pieces, then add to mixture. Heat 2 cups water to boiling and add ancho peppers. Stir occasionally, until peppers are soft. Drain and puree in blender. Add peppers to the meat mixture. Rinse blender with the remaining cup of water and add to the meat mixture. Add the chocolate candy bar and allow to simmer for approximately 1 hour.