I think whats annoying me here isn't the trope of "superior Japanese food" per se, I mean it's fairly natural she may dislike another cusine and would want to replicate her Japanese dishes.
What is bothering me, is how directly insulting it is to the other cusine. Her reaction is actual disgust about it, this would be much more readable if it was more of a "this food is kinda nice, but I miss my old food, let me show you that", more of an cultural exchange than... yea, total superiority.