"What's Cooking?" was the final short story in the book, More & More Tales to Give You Goosebumps.
The story begins with the legend of Sue Chopman, the former lunch lady at Mill Road School. In 1947, she began preparing lunches for the children, usually by going out into a forest with a cleaver and bringing back a sack full of meat. Everyday she would make a brand new meat dish but the children begun to complain about the food, especially her Chinese cooking!
This lead to the children calling her Chop Suey. As Sue continued to work at the school, the dishes got worse and worse, with children claiming to find parts of human fingers in their food. Eventually, Sue went mad and started attacking the children in the lunchroom, hacking her cleaver into the walls and tables while screaming. Years later, she died in a packing plant, when she slipped on the bloody floor and fell onto her cleaver...
Currently, in the present are two children, Diane and Robert, who are beginning summer school in the newly reopened Mill Road School. They heard that they can bring Chop Suey back to life, by standing on their toes and saying her name three times.
To test it out, Diane runs into the kitchen and as soon as she says her name three times, all the faucets turn on! So they take it as a sign. At lunch, Robert's PB+J has been replaced by raw liver and Diane's bag has been cut to shreds by forces unseen.
The next day, the cafeteria has opened and a large woman is serving hot food. She ladles out tomato soup with hot dog pieces floating on the top. As the children leave the cafeteria, they spot a sign for tomorrow's lunch: "Tomorrow's Lunch: Meat Surprise-- Aunt Sue's Special Recipe!"
The two children are halfway home after school, before Diane realizes that she left her math book in the cafeteria and there is a test the next day. Diane is just willing to fail instead of having to go back, but Robert then denies that Aunt Sue the lunch lady may really be Chop Suey.
Inside the school lunchroom, they spot Diane's book and also Chop Suey the cafeteria cook, who floats up after them waving her meat cleaver! She tells them, that they are the meat surprise! It is then Diane remembers that she saw a movie once where they said the evil spirit's name backwards and it disappeared. So they try it by saying "Suey Chop" three times fast and Chop Suey vanishes!
At home, Diane's mother tells them that they just ordered Chinese food. She starts to complain about how their father always orders the exactly same thing: Chop Suey!
Out of anger, she then says "Chop Suey, Chop Suey, Chop Suey!" Causing the children to cry out in dread...