Cook the peas in boiling broth for about 1 hour. Wash, peel and dice the potatoes. Clean, wash and cut leek into rings. Clean, wash and slice carrots.
Wash the marjoram, dab dry and pluck the leaves from the stalks. After 40 minutes of cooking, add the vegetables, half the marjoram and potatoes to the peas and cook until done. 10 minutes before the end of the cooking time, add the sausages to the soup.
Season soup to taste with salt and pepper, pour into a terrine and sprinkle with the remaining marjoram and serve garnished with parsley and coarse pepper to taste.