These rolled and filled lemon ginger cookies started out as slice and bake spirals but ended up as a rugelach. The coarse sparkling sugar finish on the outside adds a festive crunch to the tender warm spiced cookie on the inside.
In stand mixer fitter with paddle, beat butter and brown sugar at medium speed until well combined. Add the molasses and egg and beat until well blended. In another bowl, whisk flour, spices and salt until well blended. Add the flour mixture to the butter mixture and beat at low speed just until combined. Divide dough into 3 equal portions. Roll each into a 9-inch log. Place each log on a large piece of plastic wrap and press into an 11x 3-inch rectangle. Wrap in plastic and smooth out air pockets with a rolling pin. Place packets on a cookie sheet and transfer to the refrigerator. Chill dough for 30 to 60 minutes.
Filling
Prepare the filling. Melt white chocolate and butter in a double boiler, stirring occasionally. Remove bowl from heat and let cool until just warm. Add powdered sugar, flour, 1 egg yolk, lemon zest, lemon juice, lemon extract and salt. Using a handheld immersion blender, emulsify mixture until it is smooth and thickened. Set aside.
Assemble Cookies
On a lightly floured parchment covered surface, roll 1 portion of unwrapped chill dough into a 15 x 6-inch rectangle. Spread ⅓rd of the filling over the dough leaving a ½-inch wide strip on one long side at the top. Starting at the bottom long side, roll the dough into a tight coil, jelly roll style. Use the parchment to help you lift and roll the dough. Transfer the log, seam side down to the baking sheet. Repeat with remaining dough and filling. Chill 30 minutes.
Beat the egg white with a fork until loose. Brush dough logs with a thin layer of egg white and roll in demerara sugar to coat all sides. Place logs in the freezer for 30 minutes or until very firm. Heat oven to 350F. Line a baking sheet with parchment paper. Slice each log into 12 equal pieces and place on baking sheets 2-inches apart. Bake 18 minutes or until just golden brown. If any filling spills out and over browns just trim away with a sharp knife while still warm. Cool on wire rack. Makes 36 cookies.
Notes
Store in an airtight container for several days.Cookies may be sliced and frozen (unbaked). Keeps for 3 months in airtight container. Bake as needed.