Put the pork knuckles and the smoked ham in a large, heavy bowl and bring to the boil. Add the leeks, peas, celery with greens and garlic cloves, all finely chopped, as well as the marjoram, soaked in water for one night, and simmer gently on a low flame for 3 1/2 hours with the lid closed.
When the meat separates easily from the bones, it is cooked. Cut into cubes and discard the bones(*).
Strain the soup or blend it in a hand blender. Return the meat to the soup, add the smoked sausage in slices and simmer for another twelve minutes.
Only then, if necessary, season to taste with salt and freshly ground pepper and, if desired, add a little whipped cream.
(*) Walter Slezak: Do not give the bones to your dog. He could hurt himself on them, as well as on chicken bones. However, if your neighbor has one of those famous biting dogs that bark and growl a lot, feel free to throw the bones over the fence.
Tip: Always use an aromatic ham, it will give your dish a wonderful touch!