It is in fact an Indian-inspired dish, of vegetables stewed in a consommé, seasoned with spices that include a curry mixture. It contains both onion and garlic, a combination which wouldn’t occur in any original Indian curry dish.
There are many different recipes. Most are based on chicken stock. Mrs Beeton, though, said you can base the stock on any fowl, or even rabbit.
Vegetarian ones are made from split peas and vegetables simmered long and slow, so that they almost taste like a meat soup.
Eliza Acton was the first writer to record a recipe for the soup in 1845 in her “Modern Cookery for Private Families”. Her recipe did not call for any meat.
Literature & Lore
“Memories are like mulligatawny soup in a cheap restaurant. It is best not to stir them.” — P. G. Wodehouse (1881-1975).
Miss Sophie: Thank you, James. You may now serve the soup.
James: The soup, thank you very much, Miss Sophie, thank you. They are all waiting for you. Little drop of mulligatawny soup, Miss Sophie?
Miss Sophie: I am particularly fond of mulligatawny soup, James.
James: Yes, I know you are.
— May Warden and Freddie Frinton, “Dinner for One”. Recorded at Theater am Besenbinderhof in Hamburg, May 1963.
Elaine: Do you need anything?
Kramer: Oh, a hot bowl of Mulligatawny would hit the spot.
Kramer: Yeah, it’s an Indian soup. Simmered to perfection by one of the great soup artisans in the modern era.
— Seinfeld. 1995 episode.
Mulligatawny was actually a sauce in India. The word comes from a southern Indian Tamil word that means literally “pepper water.” “Molagu” means “pepper”; “thanni” means “water.”