For the dough: Pulse the flour, sugar and salt in food processor until combined. Add the butter and pulse until it resembles coarse sand with some pea-sized pieces of butter, about 20 times. Add the cream cheese and sour cream, and pulse until it comes together in a rough dough (with some uneven pebbles sized-pieces). Turn the dough out of the bowl onto a floured work surface and divide into 4 equal portions. Pat each portion into a flat square and wrap in plastic wrap. Freeze dough for 15 minutes.

Meanwhile, chop the nuts in a clean food processor. Add the preserves, raisins and salt; puree to make a very smooth paste.

Roll a portion of dough into a 6 by 14-inch rectangle about 1/4-inch thick. (Don't worry about slightly rough edges; these will be rolled inside of the rugalach.) Spread 1/4 of the filling over the surface with a small spatula. Starting with a long side, roll the dough up into a tight cylinder ending with the seam on the bottom. Press the top slightly to flatten; wrap in plastic wrap. Freeze for another 15 minutes. Repeat with the remaining dough and filling. (The cylinders can be frozen for up to a month.)

Meanwhile, evenly position the racks in the oven and preheat to 375 degrees F. Line 2 baking sheets with parchment or silicone baking mats.

Slice the cylinders into 1 1/2-inch pieces, and place rugalach seam-side down on the prepared pans. Whisk the egg yolks together and brush this glaze over the top of the rugalach. Sprinkle with sugar and bake until pale golden and crispy on top, about 25 minutes.

Remove from oven and let cool slightly on the baking sheet. Carefully transfer rugalach to a rack to cool. Serve.

Store rugalach in a tightly sealed container for up to 3 days.