Śatapatha Brāhmaṇa ("of a hundred paths") 1.6.2.5

1.6.2.5

sa vā ebhyastatpuro 'dāśayat | ya ebhyo yajñam prārocayattasmātpurodāśaḥ purodāśo ha vai nāmaitadyatpuroḍāśa iti sa eṣa ubhayatrācyuta āgneyo 'ṣṭākapālaḥ puroḍāśo bhavati

Now that (cake), which caused the sacrifice to attract (or, appear to) them, first (puras) bestowed (dâs) it upon them: hence it is (called) purodâsa, for purodâsa, doubtless, is the same as purodâsa. This same cake on eight potsherds for Agni is indispensable on both occasions (at the new- and full-moon ceremonies).