Fry the diced pork belly in 1 teaspoon of lard until light brown. Add the diced onions and brown them lightly. Add the leek and lightly brown. Pour in the broth. Add the potatoes and carrots and cook for 5-7 minutes. Then add the celery and the finely chopped celery greens. Add the bay leaf, lovage and marjoram.
Season with salt, pepper and nutmeg and simmer for 10 minutes. Check that the carrots and potatoes are done.
If you want the potato soup a little creamy and not clear, you can now take about 2-3 ladles full and puree this amount with the hand blender and then add it back to the soup. Under no circumstances should you puree the entire soup!
Then add the sausage and simmer gently for another 10 minutes. Season again with salt and pepper. Be careful with salt, the smoked sausages add extra seasoning.
Sprinkle the parsley over the soup before serving.
I always cook this soup the day in advance, it simply tastes better when it is warmed up. I serve a strong rye bread with it.