Minnie and the gang throw a surprise birthday party for Mickey. Shortly after, Minnie secretly assigns Goofy to bake a cake for Mickey. In the meantime, everyone else keeps Mickey occupied with playing music and dancing. After several unsuccessful attempts at baking a cake, Goofy buys a cake instead. When the cake is ready, everyone sings the birthday song, with Goofy arriving with the cake. Goofy, being his clumsy self, trips and accidentally throws the cake on Mickey, who smiles regardless.
Three scenes from this short were recycled from previous shorts:
The animation of Minnie putting on lipstick and fixing her hair is recycled from Mickey's Surprise Party.
The animation of Goofy sniffing the cake's aroma in the oven is recycled from The Little Whirlwind, but with Goofy in place of Minnie.
Mickey's wild dance while Minnie plays the organ was originally done by Ward Kimball for a scene initially made for The Reluctant Dragon. The sequence was scrapped and replaced by How to Ride a Horse when RKO asked for more Goofy shorts.
Pluto makes a cameo appearance in the poster, but not in the actual short.
This is the last Mickey Mouse cartoon where Minnie is topless.
The character designs in this short (for Mickey, Minnie, Goofy, Donald, Horace, Clarabelle and Clara) were notably used in the 2023 short Once Upon a Studio.