Makes 32 cookies.
Put the flour and salt in a food processor, scatter over the chunks of cream cheese and butter and pulse the machine 6 to 10 times. Then process, scraping down the sides of the bowl often, just until the dough forms large curds - don't work it so long that it forms a ball on the blade.
Turn the dough out, gather it into a ball and divide it in half. Shape each half into a disk, wrap the disks in plastic wrap and refrigerate for at least 2 hours, or up to 1 day. (Wrapped airtight, the dough can be frozen for up to 2 months.)
On a lightly floured surface, roll the dough into an 11- to 12-inch circle. Spoon (or brush) a thin gloss of jam over the dough, and sprinkle over half of the cinnamon sugar. Scatter over half of the nuts, half of the currants and half of the chopped chocolate. Cover the filling with a piece of wax paper and gently press the filling into the dough, then remove the paper and save it for the next batch.
Using a pizza wheel or a sharp knife, cut the dough into 16 wedges, or triangles. (The easiest way to do this is to cut the dough into quarters, then to cut each quarter into 4 triangles.) Starting at the base of each triangle, roll the dough up so that each cookie becomes a little crescent. Arrange the roll-ups on one baking sheet, making sure the points are tucked under the cookies, and refrigerate. Repeat with the second packet of dough, and refrigerate the cookies for at least 30 minutes before baking. (The cookies can be covered and refrigerated overnight or frozen for up to 2 months; don't defrost before baking, just add a couple of minutes to the baking time.)
Bake the cookies for 20 to 25 minutes, rotating the sheets from top to bottom and front to back at the midway point, until they are puffed and golden. Transfer the cookies to racks to cool to just warm or to room temperature.