German Frankfurter and Lentil Soup
Crack the ham bone. Chop the celery and carrots.
In a soup pot, combine the lentils, beef broth, ham bone, celery, carrots, and peppercorns. Bring to a boil, reduce to a simmer, and cook for 1½ hours. Skim off the impurities every few minutes until no more rises to the top.
Remove from heat, discarding the ham bone. Force the mixture through a coarse sieve and discard the solids. Return the strained soup to the pot. Slice the onions thinly. Cut the frankfurters diagonally into ½-inch slices.
In a small saucepan, heat the butter. Sauté the onions for 3 minutes on medium, then add the frankfurter slices and cook for another 3 minutes.
Add the onion and frankfurter mixture to the soup pot. Return it to heat and simmer for 5 minutes.
If you buy your ham bone at a butcher shop, you can usually get them to crack it for you.