The Law Code of Yājñavalkya 1.10.50

1.10.50

yady ekaṃ bhojyayec chrāddhe daivaṃ tatra kathaṃ bhavet |
annaṃ pātre samuddhṛtya sarvasya prakṛtasya ca ||
devatāyatane kṛtvā tataḥ śrāddhaṃ pravartayet |
prāsyed annaṃ tad agnau tu dadyād vā brahmacāriṇe ||
iti || (VaDh 11.30–31) 1.227 ||

"If he should feed only one Brahmin in an ancestral rite, how would the divine rite be accomplished there?
Taking up food in a vessel from all that has been prepared,
and placing it in a shrine of a deity, he should then proceed with the ancestral rite.
He should cast that food into the fire, or give it to a celibate student (brahmacārin)."
(VaDh 11.30–31) // 1.227