Cream the butter, brown sugar, granulated sugar, and salt until smooth and creamy, being careful not to overly aerate the mixture. Add the egg yolk, molasses, and vanilla and mix until it has emulsified.

Add the flour, milk powder, baking powder, baking soda, cinnamon, ginger, nutmeg, and cloves and mix until a dough begins to form. It will be crumbly at this stage, and you may think it is too dry. Drop the dough onto a piece of parchment and gently knead it with your hand until it comes together. Press into a thick sheet and place a piece of parchment paper on top. Roll out the dough to 1/4″ (or thicker, if you prefer) and refrigerate the dough for two hours or overnight.

When ready to bake, preheat the oven to 375 F. Cut the dough into shapes and place on a baking sheet a couple inches apart. They will not spread, but we want to leave some room for even heating between the cookies. To ensure they keep their shape, refrigerate the sheet of cookies for 5-10 minutes before baking. (This works out perfectly as the sheet waiting to be baked can just chill in the fridge.) 

Allow the cookies to cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely. Once they’re cooled, you can decorate them however you like!