1. Cream the cheese and butter in a large bowl until smooth and light. Add ¼ cup granulated sugar, salt and vanilla. Stir in the flour until just combined. The dough will be very sticky. Add a little additional flour if needed to make it cohesive.
2. Divide it into four equal pieces and roll each piece into a ball. Place one ball on a large piece of plastic wrap, gently press into a disk shape, and then enclose in the plastic. Repeat with the other three balls. Refrigerate for 1 hour or freeze for 20 minutes.
3. Make the filling by combining 6 Tbsp. of granulated sugar, the brown sugar, ¾ tsp. cinnamon and the pecans. Line a large baking sheet with parchment paper and set aside.
4. Remove one disk from the refrigerator; unwrap and place dough on a floured surface. Gently roll into an approximate 9-inch circle. Spread a generous ½ Tbsp. of the apricot preserves over the dough to about ¼ inch from the edge. Sprinkle evenly with a scant ½ cup of brown-sugar filling and gently press. Cut the circle into 12 wedges. Starting at the wide edge, roll up each triangle. Place the formed pastries seam-side down on the prepared baking sheet. Refrigerate for about 20 minutes or freeze for about 10 minutes. Repeat with remaining dough.
5. Preheat the oven to 350 degrees.
6. Make the topping by combining the 1½ Tbsp. granulated sugar and the ½ tsp. cinnamon.
7. Brush each pastry with the egg and milk mixture, and sprinkle lightly with sugar-cinnamon topping. Bake for 25 to 35 minutes, until well browned. Remove from oven, and let rest on the cookie sheet for 2 to 3 minutes before transferring rugelach to a wire rack. Cool completely before storing in an airtight container.
Note: Assembled pastries can be frozen and baked at a later time. Defrost partially before placing in oven, and allow extra time for baking.