Clean the leek and cut into strips. Peel and dice the onions and dice the hand cheese. Melt some butter in a saucepan, sauté the cleaned leek and an onion in it.
Top up with the broth and simmer for 10 minutes. Briefly roast the other onion in a saucepan and let the diced hand cheese melt in it, dust with flour, fill up with the leek broth and cook through. Add the creme fraiche and bind a little if necessary. Season to taste with salt and pepper.
Dice a few slices of white bread. Heat some butter in the pan and fry the white bread cubes in it until crispy. Serve the soup with the croutons on top, decorate with a pair of leek rings if necessary.