Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large bowl, cream together the softened butter and light brown sugar until light and fluffy, about 3 minutes.
Beat in the egg, then add the molasses and vanilla extract, mixing until fully combined.
In a separate bowl, whisk together the all-purpose flour, baking soda, ground ginger, ground cinnamon, ground cloves, ground nutmeg, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Stir in the rolled oats until evenly distributed throughout the dough.
Divide the dough into two portions and wrap each in plastic wrap. Refrigerate for at least 1 hour to firm up.
On a lightly floured surface, roll out one portion of dough to about 1/4 inch thickness.
Use a gingerbread girl cookie cutter to cut out shapes and place them about 2 inches apart on the prepared baking sheets.
Repeat with the second portion of dough.
Bake the cookies in the preheated oven for 10 to 12 minutes, or until the edges are set and just beginning to brown.
Remove from oven and allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.