The oven that the cake is baked in can be seen in Mickey's House at Walt Disney World including the temperature setting of "Volcano Heat".
Loose remake of 1931's 'The Birthday Party.' In this earlier short, Minnie and the Barnyard Gang throw Mickey a surprise party and he receives a miniature piano as a gift (rather than an organ).
"Mickey's Birthday Party" from 1942 is the last Mickey Mouse Cartoon where Minnie is topless.
"Mickey's Birthday Party" from 1942 is the second to last appearance of both Horace Horsecollar, Clarabelle Cow and Clara Cluck in a Mickey Mouse Cartoon until the 1983 Mickey Mouse featurette "Mickey's Christmas Carol (1983)", 41 years later. They would finally appear in the following Mickey Mouse Cartoon "Symphony Hour (1942)" from 1942. Horace and Clarabelle also appeared in the 1942 educational Cartoon "All Together (1942)", tough only with reused animation from the 1935 Mickey Mouse Cartoon "The Band Concert (1935)".
Three scenes from 1942s "Mickey's Birthday Party" were recycled from previous Cartoons: The animation of Minnie putting on lipstick and fixing her hair is recycled from the 1939 Mickey Mouse Cartoon "Mickey's Surprise Party (1939)". The animation of Goofy sniffing the cake's aroma in the oven is recycled from the 1941 Mickey Mouse Cartoon "The Little Whirlwind (1941)" (which was also directed by Riley Thomson), 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 (1941)" from 1941. The sequence was scrapped and replaced by "How to Ride a Horse (1950)" (which also got released as a standalone Goofy Cartoon in 1950), when RKO asked for more Goofy shorts.