BṚHADĀRAṆYAKA UPANISHAD · 6.4.16

अथ य इच्छेत् -- पुत्रो मे श्यामो लोहिताक्षो जायेत त्रीन् वेदान् अनुब्रुवीत सर्वम् आयुर् इयाद् इति उदौदनं पाचयित्वा सर्पिष्मन्तम् अश्नीयाताम् ।
ईश्वरौ जनयितवै ॥

atha ya icchet -- putro me śyāmo lohitākṣo jāyeta trīn vedān anubruvīta sarvam āyur iyād iti udaudanaṃ pācayitvā sarpiṣmantam aśnīyātām ।
īśvarau janayitavai ॥

Now, in case one wishes, 'That a swarthy son with red eyes be born to me! that he be able to repeat three Vedas! that he attain the full length of life!'--they two should have rice boiled with water and should eat it prepared with ghee. They two are likely to beget [him].

Robert Ernest Hume · The Thirteen Principal Upanishads (1921), Bṛhadāraṇyaka VI.4