Anandakanda 1.10.27

1.10.27

tamādāya lihedbāhye siddhacūrṇena bhairavi /
tato divyauṣadhairlipte saṃpuṭe bhūdhare pacet //

Taking it out, O Bhairavī, one should coat it on the outside with the perfected powder;
then, in an earthen capsule smeared with divine medicinal herbs, cook it in a subterranean apparatus.