In a large bowl, use an electric mixer to beat the butter and sugar at medium speed until fluffy (3 to 4 minutes). In a separate small bowl, stir together ¼ cup water and the baking soda until dissolved; stir in the molasses.
In a medium bowl, whisk together the flour, spices and salt. Add the flour mixture to the butter mixture alternately with the molasses mixture, beginning and ending with the flour mixture. Shape the dough into a ball; cover and chill 1 hour.
Preheat the oven to 350°F. Line baking sheets with parchment paper.
Roll the dough to ¼ inch thickness on a lightly floured surface. Cut with a 3-inch gingerbread people cutter. Place 2 inches apart on the prepared baking sheets.
Bake for 10 to 12 minutes. Cool 1 minute on baking sheets; remove to wire racks to cool completely. Decorate, if you'd like!