 It has also been speculated that they were introduced to the Netherlands in the 15th century by Portuguese Sephardi Jewish immigrants; the food being related to the Jewish sufganiyah traditionally eaten on Hanukkah.The earliest discovered recipe of "oliekoecken" ("oil cookies", the direct precursor of the oliebol) came from the 1667 Dutch book "De verstandige kock" "The competent cook".For centuries the Dutch ate oliekoek ("oil cookie"), an old name for oliebol ("oil ball").