Prepare dough; in large bowl, with mixer on medium speed, beat butter and cream cheese until creamy, scraping bowl occasionally. Reduce speed to low; gradually beat in flour and salt just until blended, scraping bowl occasionally. Divide dough into 4 equal pieces; flatten each into a disk. Wrap each disk in plastic wrap and refrigerate at least 4 hours or overnight, until dough is firm enough to roll.
Meanwhile, prepare filling: In medium bowl, combine apples, walnuts, and brown sugar.
Prepare Spice Sugar: In small bowl, combine sugar and cinnamon.
Preheat oven to 350. Line 2 large cookie sheets with parchment paper.
Sprinkle work surface with 2 tablespoons Spice Sugar. Place 1 disk dough on top of sugar; turn over to coat both sides. Roll dough into 10-inch round, turning round over a few times and sprinkling dough with 2 more tablespoons Spice Sugar to coat both sides.
Spread top of round with 3 tablespoons jelly, then sprinkle with 1/2 cup filling, leaving 1/2-inch border around edge. With knife, cut dough into 16 equal wedges. Starting at wide end, roll up each wedge jelly-roll fashion. Place rugelach, 1-inch apart, on prepared cookie sheet, point side down.
Bake rugelach 30-33 minutes or until dough is browned and cooked through. Immediately transfer to wire rack to cool.
Repeat with remaining dough, Spice Sugar, jelly, and filling. Store cookies in airtight containers at room temperature up to 1 week or in freezer up to 3 months. Dust with confectioners' sugar to serve.