In a heavy saucepan over medium heat, melt the butter. Cook the stew meat in the melted butter to brown it, about 6 minutes. Sprinkle with chili powder.
2.
In a food processor or blender, puree 1 cup of the beans and stir into the beef mixture. Add remaining beans whole.
3.
Cover mixture with beef stock and bring to a low boil, then simmer covered for 2 hours, adding more stock if necessary.
