Some scholars say feeding the needy once is sufficient

Hasan says that feeding once is obligatory.

Hazrat Ibn Sirin says that in expiation, gather the needy at one time and feed them until they are full.

Hazrat Saeed bin Yazid Abu Muslima narrates that I asked Hazrat Jabir bin Zaid about feeding the poor as expiation for an oath. He replied, "It is to feed them." I said, "Hasan says that for each poor person it is one and a half sa’ (measure); is one and a half sa’ of wheat not sufficient in your view?" He replied, "One and a half sa’ of wheat is not sufficient."

Hazrat Mak'hool states that for the expiation of an oath, ten needy people should be fed, as Allah Almighty has mentioned in the Holy Qur'an, until their stomachs are filled.

Hazrat Humaid narrates that before his death, Hazrat Anas fell ill and did not have the strength to fast. He gathered thirty needy people and fed them bread and meat in one meal.

Hasan says that for the expiation of an oath, bread and meat should be given in a meal until the person is satisfied.