I believe I do have a timeline of events that you might find enlightening.
Hilla is surprised that baby Debbie wants to be fed more. Jerry suggests that it’s because she is ready for her pudding. However, Hilla is heard to ask “Well, don’t you want it?”, suggesting that Debbie ultimately doesn’t want her pudding.
The baby is making raspberry noises as Hilla deals with her. Hilla requesting that Debbie saves her “the raspberries of impatience”. This leads to Jerry composing an impromptu, fruit-themed, nonsense song on the piano.
Hilla helps him to find fruit names that correctly scan within the tune.