From Webkinz Insider Wiki
Spranklebeek is a sandwich maker recipe made with bagel, broccoli, and durian.
It was solved by Webkinz Insider member monkeecj on October 19, 2012, with help from an announcement on Webkinz Newz.
This recipe was solved one year, six months, and six days after its release.
Spranklebeek was unsolved for over a year which makes it one of only nine secret recipes to have ever reached that milestone. The others are: Aminkle Grog, Boiled Wyvernacle, Epochiquox Glimmer, Gladdugrumble, Petallastar Pop, Spiny Sporcues, Tusslepuff, and Yummytummy Tumbler.