Q. If one made Kiddush (Shabbos morning after Shacharis or Musaf) and ate a kezayis of cake, or drank a cup of wine, is it OK to delay the actual seuda after chatzos? Or should one in all cases wash and eat bread prior to chatzos, like the Aruch Hashulchan says? And what is one to do if he is a guest by people who will start later?
A. Ohr Letzion (2: 21: 4) and others maintain that once kiddush has been recited and a kezais mezonos eaten, in need one may wait and eat the day seuda after midday. Horav Shlomo Miller’s Shlit’a is similar.
On question 361 we wrote: “Horav Shlomo Miller’s Shlit”a opinion (as also other Poiskim) is that if one recites Kidush and drinks a Reviis of wine (a minimum of 86 c.c.) it would already be considered as reciting Kiddush in a Seudah. It is better to drink a Melo Lugmov or a cheek full of wine followed by a complete reviis.”
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a