To make the pastry: Combine the flour, sugar and salt in a food processor and pulse a few times to mix. Add the butter and pulse until the butter pieces are about the size of bread crumbs. Add the cream cheese and process until the dough begins to clump together, about 30 seconds. Turn the dough out onto a work surface and divide it into 4 pieces. Press each piece into a flat patty about 4 inches in diameter, wrap in plastic wrap, and refrigerate until firm, about 4 hours.

Position the racks in the upper and lower thirds of the oven and preheat the oven to 350 degrees F. LIne two cookie sheets with parchment or wax paper or aluminum foil.

To make the filling: Mix the sugars, cinnamon, nibs and currants together in a medium bowl.

Remove one piece of dough from the refrigerator. Roll it out between two pieces of wax paper into a 12-inch circle a scant 1/8 inch thick. Peel off the top sheet of wax paper and place the paper on a counter or cutting board. Flip the dough onto the paper and peel off the second sheet. Sprinkle a quarter of the filling over the dough. Gently roll over the filling with a rolling pin to press it into the dough. Cut the dough into 12 equal wedges like a pie. Starting at the wide end of one wedge, roll it up and place it, with the dough point underneath to prevent it from unrolling, on one of the cookie sheets. Repeat with the remaining wedges, placing them 1 1/2 inches apart.

Repeat with the remaining dough and filling. (If at any time the dough becomes too soft to roll, return it to the refrigerator to firm up.)

Bake, rotating the sheets from top to bottom and front to back halfway through the baking time, for about 25 minutes, or until light golden brown at the edges. Set the sheets on racks to cool completely. (The rugelach are best on the day they are baked, but they can be stored, airtight, for about 5 days.)