But in "no true Scotsman" there's an assumption that there's an external definition of the Scotsman category that is invariant from the fallacious clause, where

But in "no true Scotsman" there's an assumption that there's an external definition of the Scotsman category that is invariant from the fallacious clause, whereas here the definition of the grilled cheese category is the system under question. Otherwise, I could say "yes, I like grilled cheese, especially when it isn't grilled and contains neither cheese nor bread."