Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.1.27

2.6.1.27

sa upastṛṇīta ājyam | athāsya puroḍāśasyāvadyati sa tenaiva saha dhānānāṃ tena saha manthasya tatsakṛdavadadhātyathopariṣṭāddvirājyasyābhighārayati pratyanaktyavadānāni nātikrāmatīta evopotthāyāśrāvyāha pitṝntsomavato yajeti vaṣaṭkṛte juhoti

[The Adhvaryu] makes an 'under-layer' of butter (in the guhû or offering-spoon). He then cuts a piece from the cake, and together therewith some of the parched grain and the porridge. This he puts down at the same time (in the guhû); makes two sprinklings of butter thereon; and re-anoints (replenishes with butter, the parts of the sacrificial dishes from which he has made) the cuttings. He does not walk over (to the south side of the fire); but having risen and stepped up (to the fire) on the same side (where he was seated), and called (on the Âgnîdhra) for the 'Sraushat,' he says (to the Hotri), 'Pronounce the offering-prayer to the fathers, accompanied by Soma!' and pours the oblation (into the fire) as soon as the Vashat has been uttered.