Bring the water to boil with bouillon cubes or beef broth and put the leeks cut into rings.
Brush the potatoes firmly, cut them into pieces with the peel, add them to the soup with the caraway seeds and salt and pepper, cover and boil for about 20 minutes.
Meanwhile, boil the corn on the cob in another pot in unsalted water. After 20 minutes mash the potato leek soup.
Rub the corn on the cob with a knife and add the kernels to the soup, season a little and serve.