Peel, wash, and chop the potato and onion. If you don't want to weep while cutting the onion, you can use a universal electric chopper (if available) for this purpose.
Heat the butter in a pot and sauté the onion in it until translucent.
Add the potatoes and infuse with the clear chicken broth.
Cover and simmer gently for 10 minutes.
Add the corn and cook gently for another 10 minutes.
Next, add crème fraîche, salt, pepper, and the tap water, and liquidize the soup with the immersion blender.
Finally, to make the soup quite subtle, pass it with a tablespoon through a close-meshed sieve into a large bowl or cooking pot.
After straining, pour the soup back into the pot and bring to a boil again.
Voilà, your smooth and delicious corn soup is ready-made and able to be served!