In a large soup pot add onions, potatoes and farmers sausage, cover with water approximately 12 cups. Allow to come to a boil. Cook over medium heat till sausage begins to split.
Add beet tops, sorrel, dill, salt and pepper. Add buttermilk - this will become a little clumpy looking as the beet tops add a level of sourness to the soup that combined with the natural sourness of the buttermilk - will create some cruds. Remove the sausage and cut into bite size pieces return to the soup - and serve with cream on the side for those who might like it a little creamier.