Malted Milk Chocolate Rugelach

Directions

1. Make the dough: In the bowl of a food processor fitted with the blade attachment, combine the flour, sugar, ¼ cup malted milk powder, and salt. Process until combined, 10 to 15 seconds. Add the butter and cream cheese and process until a rough, shaggy dough forms that just starts to pull away from the sides of the food processor, 30 to 45 seconds. (If you don’t have a food processor you can pinch and knead the butter and cream cheese into the dry ingredients using clean hands as if you are making pie dough.) Transfer the dough onto a lightly floured work surface, cut in half, and roughly form each half into a rectangle. (Wipe out the food processor, but don’t wash it.) Tightly cover in plastic wrap and chill in the refrigerator for at least 2 hours, up to overnight.
2. Make the filling: Place the chocolate chips, malted milk powder, cocoa powder, cinnamon, and salt in the bowl of a food processor fitted with a blade attachment and process until the mixture is the texture of coarse sand, 25 to 35 seconds. (Alternatively, chop the chocolate into a fine dust and mix with the other ingredients.) Transfer into a bowl and set aside. In another small bowl, crack the egg for the egg wash and beat with a fork until no streaks of unincorporated yolk remain.
3. Unwrap one of the chilled doughs, generously dust with flour, and roll into a 11- by 8-inch rectangle. (The dough can get sticky, so use a bit more flour than normal.) Trim the edges to create crisp lines, if desired. Sprinkle about half of the filling onto the dough in an even layer leaving a ½-inch border on the top and bottom, pressing it in with your hands so it sticks and compacts slightly. Brush the top and bottom border with the egg wash. Roll into a spiral shape, brushing the underside of the dough with egg wash each time you roll it over, and transfer onto a sheet pan. Repeat with the remaining dough and filling and freeze both logs uncovered for 1 hour.
4. As the cookie logs are chilling, preheat the oven to 350°F and set 2 racks at the upper-middle and lower-middle positions. Line 2 baking sheets (you can line the one in the freezer once the logs are done chilling) with parchment paper or nonstick baking mats.
5. Brush the chilled dough logs with the egg wash on all sides. (If your egg wash has a lot of chocolate in it, it’s best to make a new one.) Generously sprinkle the tops of the logs with the sanding sugar. Cut the logs into 1½-inch thick slices using a thin sharp knife and place onto the prepared baking sheets spacing at least 2 inches apart. Bake for 30 to 40 minutes until lightly browned, then let cool completely on the baking sheet before serving. (If any of the rugelach spread more than you would have liked, just use the back of a spoon to push them back together while still hot from the oven.)