Śatapatha Brāhmaṇa ("of a hundred paths") 1.7.3.27

1.7.3.27

uto gārhapatya eva śrapayanti | āhavanīyo vā eṣa na vā eṣa tasmai yadasminnaśṛtaṃ śrapayeyustasmai vā eṣa yadasmiṃcūtaṃ juhuyurityato yatarathā kāmayeta tathā kuryāt

However, they also do cook on the Gârhapatya, arguing, 'The former is indeed âhavanîya (i.e. "suitable for a burnt-offering"); but that one, surely, is not (intended) for this,--viz. that they should cook uncooked (food) on it; but it is (intended) for this,--viz. that they should offer up cooked (food) on it.' He may therefore do it on whichever (fire) he pleases.