8ouncescold, unsalted butter, cut into 1/4" chunks, (2 sticks/1 cup)
8ouncescold cream cheese, cut into 1/2" chunks, (1 cup)
1/2cupsugar , (I use organic turbinado)
1 1/3cupsfinely chopped pistachios
1 1/3cupsfinely chopped bittersweet chocolate , (see headnote)
Make the dough:
In the bowl of a food processor, combine the flour, sugar and salt. Scatter the butter pieces, cream cheese, and sour cream over the top, and pulse about sixteen times until the dough just clumps together - it will look like chunky cottage cheese. (You can also do this in a stand mixer fitted with the paddle attachment, or, probably, by hand the way you would make pie dough.) Turn the dough out onto a lightly floured surface and divide it into 4 equal portions. Press each portion into an 8x4" rectangle, wrap in plastic, and chill for at least 30 minutes or up to 2 days (or place the dough in a freezer bag and freeze for up to 1 month; defrost in the fridge overnight before using).
While the dough chills, prepare the filling ingredients:
Stir the sugar and salt together in a small bowl. Have the chopped chocolate and nuts standing by in small bowls.
Assemble and bake the cookies:
Remove a dough rectangle from the fridge and place it on a lightly floured surface. Roll the dough into a 12x8" rectangle with a long side facing you - it will be about 1/8" thick. Trim the edges clean. Leaving a 1" boarder on the top edge, sprinkle the dough evenly with 2 tablespoons of the seasoned sugar. Sprinkle 1/3 cup of the chocolate over the sugar, then 1/3 cup of the chopped nuts. Use your hands to gently but firmly press the filling into the dough. Starting from the bottom edge, roll the dough up into a tight cylinder with the seam on the bottom. Cut the cylinder into 3/4-1" lengths. Place the cut rugelach seam-side-down on a sheet pan and place the pan in the freezer.
Repeat with the remaining rectangles of dough, and freeze all the rugelach until firm, at least 20 minutes.
While the rugelach freeze, position racks in the upper and lower thirds of the oven and preheat to 375º. Place the frozen rugelach 2 inches apart on sheet pans lined with parchment paper. Bake the rugelach until golden on top, rotating front to back and top to bottom halfway through baking, about 20 minutes.
Immediately remove the rugelach to cooling racks so that they don't form a foot of sugary goo around their bases and let cool completely.
Rugelach keep well for up to 5 days at room temperature in an air-tight container.
Adapted from Baking Illustrated and Alice Medrich.This classic dough can handle many variations: smear a slick of smooth jam over the dough, swap out any nut for the pistachios, trade the chocolate for dried currants, and add cinnamon or cardamom to the sugar.As always, be sure to use a good chocolate that you like the flavor of on its own; I used Scharffenberger's bittersweet chocolate which has a cacao mass of 70%. If I were to use a sweeter chocolate, I would decrease the sugar. But that's just me.You have several do-ahead options for rugelach: freeze the dough for up to 1 month, or assemble and fill the rugelach and freeze them, unbaked, for up to 1 month, then bake them straight from the freezer.Nutritional values are based on one of forty rugelach.