In a large microwave-safe bowl, place the butter and heat in 20 second increments until melted. Add in the brown sugar, molasses, and spices.
When the mixture has slightly cooled, whisk in the beaten egg.
Sift in the flour, baking powder and baking soda, and mix until no traces of flour is visible.
Pat the dough into a thick rectangle and wrap well with plastic wrap or parchment paper. Place the dough into the fridge to chill for at least 1 hour.
Preheat oven to 350F.
After the dough has chilled, remove from fridge and dust a rolling pin with flour. Roll the dough to about ⅛" thickness and using a cookie cutter dusted with a little flour, cut out shapes as desired.
Place the cut out shapes onto a baking sheet lined with parchment paper.
Bake the cookies for 8-12 minutes until slightly brown, or lightly firm. Let cookies cool on the rack for 5 minutes before transferring to a cooling rack to completely cool.
Decorate the cookies if you wish or eat them as is.
Cookies may be stored in an airtight container for up to 2 weeks.