Sift the flour, baking soda, salt, ginger, cinnamon, cloves and allspice into a medium bowl; set aside. Melt the butter and shortening in a medium saucepan; remove from the heat and stir in the brown sugar and molasses. Transfer to a large bowl and let cool slightly.
Add the egg to the butter mixture; beat with a mixer on medium speed until incorporated. Reduce the mixer speed to low; beat in the flour mixture in two additions until just combined. Divide the dough in half; wrap each half in plastic wrap and pat into 1/2-inch-thick disks. Refrigerate until firm, at least 2 hours.
Position racks in the upper and lower thirds of the oven; preheat to 350 degrees F. Line 2 baking sheets with parchment paper. Working with 1 piece of dough at a time, roll out the dough to 1/4 inch thick on a lightly floured surface, dusting with flour as needed. Cut out gingerbread men with a 3 1/2- to 5-inch cookie cutter and arrange 1 inch apart on the prepared baking sheets. Brush off the excess flour and refrigerate the cutouts 15 minutes.
Bake the cookies until golden around the edges, 10 to 12 minutes. Let cool 3 to 5 minutes on the baking sheets, then transfer to racks to cool completely. Decorate with royal icing and let harden at room temperature, about 1 hour.