Rugelach

Make the dough: In the bowl of an electric mixer fitted with the paddle attachment, beat together butter and cream cheese at medium speed. Add sugar, and beat until fluffy. Beat in egg yolks, one at a time, beating to combine after each addition. Add vanilla and salt, and beat to combine. Reduce speed to low, and beat in flour. Remove from bowl, and divide into 3 pieces on a lightly floured surface. Pat into disks, and wrap in plastic wrap. Refrigerate for at least 1 hour, and up to overnight.

Make the filling: In a food processor, combine walnuts, sugar, cinnamon, and salt. Pulse until fine.

Preheat the oven to 350 degrees. Line baking sheets with Silpats (French nonstick baking mats). On a lightly floured surface, roll one piece of dough into a 12-inch round, less than 1/8 inch thick. Brush evenly with jelly. Sprinkle with one-third of the walnut mixture and one-third of the chocolate chips. Using the rolling pin, gently roll over filling to press ingredients into dough.

Cut the round into 16 equal-sized wedges. Beginning at the base of each wedge, roll to enclose filling, forming crescent shapes. Pinch to seal. Place on prepared baking sheets. Repeat with remaining dough and filling ingredients. Brush tops with beaten egg, and sprinkle with sanding sugar. Bake until golden brown, 20 to 25 minutes.