Śatapatha Brāhmaṇa ("of a hundred paths") 5.5.2.6

5.5.2.6

āgneyo 'ṣṭākapālaḥ puroḍāśo bhavati | saumyaścaruḥ sāvitro dvādaśakapālo vāṣṭākapālo vā puroḍāśo bārhaspatyaścarustvāṣṭro daśakapālaḥ puroḍāśo vaiśvānaro dvādaśakapāla etāni ṣaṭ pūrvāṇi havīṃṣi bhavanti

There is a cake on eight potsherds for Agni, a pap for Soma, a cake on twelve or eight potsherds for Savitri, a pap for Brihaspati, a cake on ten potsherds for Tvashtri, and one on twelve potsherds for (Agni) Vaisvânara--these are the first six oblations.