1. Rinse beans. In a 4- to 6-quart Dutch oven combine beans and the 8 cups water. Bring to boiling; reduce heat and simmer 2 minutes. Remove from heat. Cover; let stand 1 hour. (Or, do not precook beans. Soak them in water overnight in a covered pan.) Drain beans and rinse.
2. Trim excess fat from meat. Combine the 2-1/2 teaspoons Garam Masala and the salt; rub the mixture onto meat. In the same Dutch oven brown meat on all sides in hot oil. Drain off fat.
3. Pour beef broth over roast. Add soaked garbanzo beans. Bring to boiling; reduce heat. Cover and simmer for 1-1/4 hours. Add carrots and onions to meat. Return to boiling; reduce heat. Simmer, covered, for 45 to 60 minutes more or until meat and vegetables are tender. Transfer meat and vegetables to a platter.
4. After removing meat and vegetables from Dutch oven, pour drippings into a large measuring cup, scraping out the crusty brown bits from the pan. Measure 1 cup for sauce (cover and refrigerate remainder for another use or discard).
5. For sauce, return the 1 cup reserved cooking liquid to the Dutch oven. Stir in the 1 teaspoon Garam Masala. Bring to boiling. In a screwtop jar shake together cornstarch and the 2 tablespoons cold water; add to the Dutch oven. Cook and stir until thickened until bubbly.
6. Cook and stir for 2 minutes more. Remove from heat; stir in yogurt until well combined. (Do not return to heat.) Serve sauce with meat and vegetables. Accompany with Indian pappadams or tortillas, if desired. Makes 10 to 12 servings.