Hi. What is the Shiur of bread one should eat at Shabbat Seudahs? I’ve heard both that one has to eat a Kzayit and a Kbaytza. What is the correct Shiur. Thank you!

ב"ה Shalom, The Shulchan Aruch Hilchot Shabbat (291:1) says thata "k'betza of bread is necessary to fulfill the requirement of a Shabbat meal. The Mishna Brura there adds, that actually more than a K'betza is required because, according the Shulchan Aruch elsewhere (232:3) a k'betza is still considered a temporary meal. However, the Mishna Brura also cites another opinion that a K'zait is sufficient so the Mishna Brura sums up that the correct thing is to be stringent and one should have a "K'betza". All the best