Sift the flour, baking soda, and spices into a medium bowl; set aside.
In a glass measuring cup whisk the molasses, water and crystallized ginger. Set aside.
Beat 3/4 cup sugar and butter and vanilla until well combined, about 1 minute with mixer.Add egg and mix well. Scrape down sides and bottom of bowl with a rubber spatula. In thirds, starting with the flour mixture, alternately add flour and molasses mixtures, occasionally scraping the bottom and sides of the bowl. Scrape the dough into a 16 x 12-inch piece of parchment. Create dough into an 11 – 12 in log.* Chill dough until very firm, at least 4 hours or overnight.
Position racks in the center and top third of the oven and preheat to 350 degrees F. Line two large baking sheets with parchment paper (these cookies bake best on parchment paper) or butter and flour the baking sheets.
Place cinnamon spice sugar or other sugar in a small bowl. Unwrap the dough and cut into 1/4 inch rounds. Gently dip both sides of cookie in the sugar. Arrange cookies about 2 inches apart on the prepared sheets. Bake, switching the position of the sheets from top to bottom and front to back halfway during baking, until the edges of the cookies are barely browned, about 14 minutes.
Cool on the sheets for 2 minutes, then transfer to wire cooling racks and cool completely.
If you prefer, you can chill the dough until fairly firm, then scoop out dough into large walnut-sized balls, roll in the sugar, then press down with the bottom of a flat glass. Follow the baking instructions.