In a medium bowl, whisk together the flour, ground ginger, cinnamon, baking soda, nutmeg, and salt. Set this aside.
In a large bowl using a hand or stand mixer, beat the softened butter and brown sugar on medium speed until the mixture is light and fluffy, about 3 minutes.
Add the molasses, egg, and vanilla to the butter mixture. Beat again until everything is well combined, scraping down the sides of the bowl as needed.
With the mixer on low, gradually add the dry flour mixture to the wet ingredients. Mix just until a uniform dough forms. Do not overmix.
Divide the dough in half. Form each half into a flat disk and wrap tightly in plastic wrap. Refrigerate for at least 4 hours or overnight.
When ready to bake, preheat your oven to 350°F (175°C). Line baking sheets with parchment paper.
On a lightly floured surface, roll one disk of dough to about 1/4-inch thickness. Cut into shapes with cookie cutters and place them about 1 inch apart on the prepared baking sheets.
Bake for 8 to 10 minutes, or until the edges are firm and just beginning to darken. The centers will still be slightly soft.
Let the cookies cool on the baking sheet for 2 minutes before transferring them to a wire rack to cool completely before decorating.