This is how I make beef soup. It's a day-long process and produces a beef soup with amazing depth and flavor. Much of the stock process comes from the advice of my father. If you have large and meaty soup bones, use two, otherwise use 3. Roasting the bones prior to making the stock makes a world of difference in flavor. Be sure to leave the skin on the onion. It will also add significantly to the flavor and color of the stock. The soup (after the stock is made) is mostly taken from Jeff Smith's (Frugal Gourmet) recipe for Beef Barley Soup, but I swap yellow potatoes for the barley because it is better in texture. For the lemon peel, just use the zest. Simply use a grater to peel a small 1" x 1/2" or so piece and drop it in the soup. The lemon is really surprisingly wonderful.