In a small mixing bowl, add the butter and brown sugar. Use a hand held mixer and beat on medium speed until smooth and creamy. Add in the egg yolk, molasses, and vanilla extract. Continue to beat until the yolk and molasses are mixed in well. The batter may look a little curdled - which is ok.
Sprinkle, or sift, the flour, baking soda, cinnamon, nutmeg, cloves, ginger, and salt over the top of the wet ingredients. Mix on low speed until not dry streaks remain.
Pour the dough onto a piece of plastic wrap and gently form into a disc. Cover the dough tightly in the plastic wrap and refrigerate for at least 1 hour.
Preheat the oven to 350o degrees and adjust the oven rack to the middle position. Line two baking sheets with parchment paper.
Remove the dough from the fridge and place on a lightly floured work surface. Roll the chilled dough to 1/4 inch thickness. If you want thicker cookies, don't roll the dough so thin.
Use a cookie cutter to cut out your shapes, and place the cookies at least 2 inches apart on the baking sheet. Re-roll any scraps to cut into more cookies. I don't recommend re-rolling the dough more than twice.
I recommend baking one baking sheet of cookies at a time. While the first batch is baking, refrigerate the other baking sheet of cookies. If the cookies feel as though they got too warm while rolling and cutting, place both baking sheets in the refrigerator to cool for about 10 minutes.
Bake the cookies for 8 to 10 minutes, or until the edges are set. If you want crispier cookies, bake for a couple minutes longer. Cool the cookies on the baking sheet set on a wire cooling rack for 10 minutes. Then transfer the cookies to the cooling rack to cool completely.
Once the cookies are cool, make the royal icing and decorate the cookies!