Damn...Why couldn't the manga be about those two instead.
Honestly, if the story followed her growth in becoming a proper person with the butler teaching her those usual "how to be a good person" lessons and ending with her shaping up and becoming more social with our protag, I wouldn't mind such a story. It think it would be a great side story with a focus on relationships rather than food.
But if it were some trashy manga that focuses entirely on her trashy nouveau riche and how her butler copes like a villainess-lite with her personality resrtting to the status quo every chapter to extend the story, it would absolutely be terrible.