Directions

1. Bring brown sugar, molasses, ginger, and 1/4 cup water to a simmer in a saucepan, whisking until sugar has dissolved. Simmer until slightly thickened, 1 to 2 minutes. Pour syrup into a bowl; let cool.
2. Whisk granulated sugar, salt, and spices in a bowl. Lightly sprinkle sugar mixture over a clean work surface; place puff pastry on top. Cut into two 10 1/2-by-7-inch pieces. Sprinkle generously with sugar mixture; press into pastry with a rolling pin. Brush generously with syrup.
3. Working with 1 piece of dough at a time, roll in from both long sides, meeting in the center; brush with syrup to seal. Sprinkle generously with sugar mixture. Wrap in plastic, and freeze until firm, at least 3 hours (up to overnight).
4. Preheat oven to 425 degrees. Cut dough crosswise into 1/2-inch-thick slices. Dip slices in sugar mixture. Space 2 inches apart on a parchment-lined baking sheet. Flatten with your palm. Freeze 30 minutes.
5. Bake 10 minutes. Flip, and brush with syrup. Reduce oven temperature to 400 degrees. Bake until darkened, 10 minutes more. Transfer palmiers to a wire rack; let cool completely. Palmiers can be stored in an airtight container up to 3 days.