3 cups all-purpose flour, plus more for work surface
1/2 tsp baking soda
1/4 tsp baking powder
1/2 cup unsalted butter
1/2 cup packed dark-brown sugar
2 tsp ground ginger
2 tsp ground cinnamon
3/4 tsp ground cloves
1/2 tsp finely ground pepper
3/4 tsp coarse salt
1 large egg
1/2 cup unsulfured molasses
Sift together flour, baking soda, and baking powder into a large bowl. Set aside.
Put butter and brown sugar in the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until fluffy. Mix in spices and salt, then eggs and molasses. Reduce speed to low. Add flour mixture; mix until just combined. Divide dough into thirds; wrap each in plastic. Refrigerate until cold, about 1 hour.
Preheat oven to 350 degrees. Roll out dough on a lightly floured work surface to a 1/4-inch thick. Cut into snowflakes with a 7- inch snowflake-shape cookie cutter. Space 2 inches apart on baking sheets lined with parchment paper, and refrigerate until firm, about 15 minutes.
Bake cookies until crisp but not dark, 12 to 14 minutes. Let cool on sheets on wire racks.