Uneeq,
The poskim (e.g. Chochmas Adam) are mattir milchig cake because it’s not the derech to eat it with milk. Apparently, pastries, even though not bread, are otherwise included in the issur.
Hello99,
Since milchig or fleishig bread are assur, and intention doesn’t help, there should most certainly be an issue of ein m’vatlin here. See the Gilyon Maharsha’s wording, in quoting the Tzemach Tzedek, who learns this way. See, however, Badei Hashulchan who seems to bring it your way.
Do you understand R’ Schachter’s ???? ???????? I don’t; if it’s batul, why not eat it with a hamburger? (I still don’t understand why it’s batel – they obviously put it in for the taste!)