Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.3.8

2.4.3.8

ta u ha viśve devā ūcuḥ | anayorvā ayaṃ dyāvāpṛthivyo raso hanteme asminnābhajāmeti tābhyāmetam bhāgamakalpayannetaṃ dyāvāpṛthivyamekakapālam puroḍāśaṃ tasmāddyāvāpṛthivya ekakapālaḥ puroḍāśo bhavati tasyeyameva kapālamekeva hīyaṃ tasmādekakapālo bhavati

The All-gods spake, 'This sap (of the rice and barley plants) truly belongs to those two, heaven and earth: let us, then, allow those two a share in it!' They accordingly assigned that share to them, to wit, the cake on one potsherd offered to heaven and earth. This is why there is a cake on one potsherd (kapâla) for heaven and earth. Now this (earth) is, doubtless, the cup (depository, kapâla) of that (sap); and she indeed is one only: hence (the cake) consists of one potsherd.