In a bowl, whisk together the flour, ground ginger, cinnamon, baking soda, nutmeg, and salt until thoroughly combined. This ensures your spices are evenly distributed and avoid pockets of flavor.
In a separate bowl, beat the softened butter and brown sugar until light and fluffy. Then blend in molasses, egg, and vanilla until fully incorporated and smooth.
Gradually add the dry mixture to the wet mixture while mixing at low speed until the dough comes together without streaks. You’ll have a fairly stiff dough.
Shape the dough into a disk, wrap it with plastic wrap, and refrigerate for at least 4 hours (or overnight). Chilling firms the dough and helps preserve the shape during baking.
Once chilled, roll the dough on a lightly floured surface to about ¼ inch thickness. Use your gingerbread man cutter to stamp shapes, placing them about 1 inch apart on ungreased baking sheets.
Bake in a preheated 350 °F (175 °C) oven for 8 to 10 minutes, until edges are set and only just browning. Let cookies rest for 1–2 minutes, then transfer to a wire rack to cool fully before decorating.