Mickey’s Surprise Party
Minnie is baking cookies. When she leaves for a short while, her dog Fifi accidentally drops popcorn kernels in the dough. Mickey and Pluto come over and visit with Minnie and Fifi. When Mickey notices that something is burning, Minnie remembers the cookies, which are popping popcorn out of them. Minnie is upset and lies on her sofa crying. Mickey goes out and buys a large amount of cookies. He comes back and shows them to her and she is overjoyed.
Made as a promotional film for the National Biscuit Company and shown at the 1939 New York World's Fair rather than in ordinary cinemas — which is why it looks like a normal Mickey short but keeps drawing attention to the biscuits. Disney's commercial and industrial work is a large and mostly invisible part of its history, and this is one of the more charming survivors.