Simone's favorite food is imaginary soup, so I am not sure I can help you with the palate expanding, unless you meant expanding it beyond the realm of the real (in which case imaginary tea is another popular choice).
Simone does not cleave to my narrow, restrictive, bourgeois definition of food, and will turn away from whatever I place before her to ladle more invisible beef goddamn bourguignon into her mouth while making exaggerated "MMMMM!" sounds. The exception is blueberries. She loves the little bastards.