Heat the butter, molasses, honey, and brown sugar in a saucepan over medium heat. Once the butter is completely melted, and all of the ingredients are well combined, remove the saucepan from the heat and set aside to cool for 10 minutes.
1/2 cup butter, 5 tbsp molasses, 5 tbsp honey, 1/3 cup dark brown sugar
When the butter mixture has cooled, whisk in the egg yolks, vanilla, and milk.
2 egg yolks, 1 tsp vanilla extract, 1 tbsp milk
Combine the dry ingredients in a separate bowl. Add the dry ingredients to the wet ingredients and mix until a dough forms. The dough will be crumbly.
3 2/3 cups all-purpose flour, 1 tsp baking powder, 1/2 tsp salt, 2 tsp ground ginger, 1 tsp cinnamon, 1/2 tsp ground cloves, 1/4 tsp nutmeg
Divide the dough in half and shape into two discs. Wrap each disc tightly in plastic wrap and chill in the refrigerator for at least 2 hours or overnight.
Preheat your oven to 350 degrees F. Remove the chilled dough from the refrigerator, and roll out one disc at a time on a lightly floured surface to ¼-in thick. Use cookie cutters to cut out the cookies and transfer them to the prepared baking sheets.
Place the baking sheets in the freezer for 10 minutes, then bake for 8-10 minutes.
Cool the gingerbread cookies completely on wire racks before decorating.
Once your gingerbread cookies have completely cooled, make the royal icing (instuctions below).
Pipe or spread the icing on the cookies and immediately top with decorative sugar. Allow the icing to set completely.