One of the Misvot at the Seder on Pesah is to eat Masa; Halacha requires one to eat two Kezetim of Masa at the Seder.
What is the time frame within which the two Kezetim of Masa must be eaten?
Hacham Ben Sion Abba Shaul (Israel, 1923-1998) addresses this question in his work of responsa Or Le’sion (vol. 3, 15:13; listen to audio recording for precise citation). He writes that ideally, one should place the two Kezetim of Masa in his mouth all at once, chew it very well, and then swallow it. Ideally, one should swallow all the Masa at once. If this is too difficult, one should swallow one Kezayit, and then swallow the rest afterward.
If one finds himself unable to put all the Masa in his mouth at the same time, then he should at least eat the entire amount within a period of four minutes, starting from the time he begins swallowing the Masa. (The time spent chewing does not count toward the time limit.) An ill or elderly person, who cannot eat so quickly, should endeavor to eat all the Masa within 6-7 minutes. If even this is too difficult, then he should try to eat the Masa within nine minutes.
Summary: Ideally, when one fulfills the Misva of Masa at the Seder, he should place all the Masa in his mouth at the same time, chew it, and then swallow it all at once. If this is too difficult, he should eat the Masa within four minutes, and those who cannot eat quickly should eat the Misva within no more than nine minutes, and preferably within 6-7 minutes.