½cupunsalted butter,room temperature (113g or 4oz)
6ouncescream cheese,room temperature (170g)
1large eggseparated (white reserved for brushing on top)
3tablespoonscoarse or sparkling sugarfor topping
Preheat oven to 350°F. Line two large baking sheets with parchment paper and set aside.
Unwrap 5 chocolate bars and break each crosswise along the 3 seams to yield 4 rectangles. You will have 20 chocolate pieces total. (Reserve the last chocolate bar for drizzling.) Set aside.
In a medium bowl whisk together the flour, salt, baking powder and 1 tablespoons sugar.
In a large mixing bowl combine the butter and cream cheese. Beat on medium until blended. Add the vanilla and one egg yolk. Blend until smooth. Add half the flour mixture and beat on low until incorporated. Add the remaining flour and mix just until the dough starts to come together.
Transfer the dough to a lightly floured work surface. Knead by hand about 25 strokes until the dough is pliable. Add a little more flour to the work surface, and roll the dough into a 20 by 8-inch rectangle. Cut the dough into twenty 4 by 2-inch rectangles.
Working with 1 piece of dough at a time, place 1 chocolate piece crosswise across the dough so the chocolate extends over the edges of the dough. Fold the dough up and around the chocolate. Place the cookie seam side down, about 2-inches apart on the prepared pan. You should be able to fit 10 cookies per pan. Repeat with remaining dough and chocolate pieces.
Brush the cookies all over with the lightly beaten egg white. Sprinkle with coarse sugar and bake until light golden brown, about 18 - 22 minutes. Don’t over bake!
Cool the cookies on the pan for 5 minutes, then transfer to a wire rack to cool completely.
Break the remaining chocolate bar into small pieces and place in a small bowl. Microwave at 50% power, stirring occasionally, until melted. Drizzle the melted chocolate over the tops of the slightly warm or cooled cookies. Allow the chocolate to set before serving or storing. Serve slightly warm, if desired.
Store at room temperature in a sealed container for up to 3 or 4 days.