"A stone faced immigrant chef with Stalinesque moustache, he is renowned throughout Manhattan for his soups." (https://en.wikipedia.org/wiki/The_Soup_Nazi)
It aired on November 2, 1995. It is arguably the most famous Seinfeld episode. Jerry, Elaine and George visited a soup stand that Kramer raved about. Jerry explained to his friends the strict protocol that the owner enforced when ordering soup. George complied, but Elaine refused; the latter was tossed out.
George returned and ordered more soup, this time complaining that he didn't receive the complimentary bread. The Soup Nazi said that the bread cost $2.00; George balked and the owner raised it to $3.00. George still complained and the owner barked: "No soup for you!"
Jerry returned with his girlfriend, and the tow were kissing in line. The owner complained; Jerry's girlfriend didn't like being reprimanded and voiced her protest. The Soup Nazi kicked her out as well. Jerry pretended he didn't know her so he could still purchase soup.
Elaine bought an armoire which was stolen on the streets of Manhattan. Kramer explained the plight of his friend to the Soup Nazi who offered his own armoire as a replacement. Elaine visited the soup stand to thank him, only to be told he wouldn't have offered it if he had known it was going to her.
Elaine later discovered the secret soup recipes in the armoire and returned to the soup stand to gloat.
Seinfeld and his cohorts visited the soup stand weeks after the episode aired. The real Soup Nazi, Al Yaganeh did a triple take, proceeded to shout out profanities and ejected the men from the restaurant.
Soup Nazi courtesy http://screencrush.com/soup-nazi/.