In a small bowl, dissolve yeast in warm water. In a bowl, combine the butter, sour cream, eggs, sugar and salt. Add yeast mixture and flour; beat until smooth (do not knead). Place in a greased bowl, turning once to grease top. Cover and refrigerate overnight.
For filling, in a bowl, beat cream cheese, sugar, egg yolk and vanilla until blended. Punch dough down. Turn onto a lightly floured surface; divided in half. Roll out each portion into a 16-in. x 10-in. rectangle on a greased baking sheet. Spread filling down center of each rectangle. On each long side, cut 1-1/2-in.-wide strips about 3 in. into center. Starting at one end, fold alternating strips at an angle across filling. Pinch ends to seal. Curve one end, forming a candy cane. Cover and let rise until doubled, about 1 hour.
Bake at 350° for 20-25 minutes or until golden brown. Carefully remove from pans to wire racks to cool. Sprinkle with confectioners' sugar. Stir jam, then spoon over top of leaves, creating candy cane stripes. Refrigerate leftovers.