Preheat oven to 375° F. Set out cookie sheet(s).
In a large mixing bowl (I used my KitchenAid), combine cup ¾ butter, ½ cup brown sugar, ½ cup granulated sugar, and 1 T orange zest (if using). Beat on med-high until fluffy.
Add the pumpkin, egg yolk, and vanilla. Beat well until combined.
Add 1 tsp cinnamon, 1/2 tsp nutmeg, and 1/4 tsp cloves, and mix until combined. Tailor the spices to your own taste. I think I was pretty generous with my 1 tsp cinnamon, and the other spices as well.
Gradually add in 1 tsp baking powder and 2 3/4- 3 cup flour until you have a soft dough.
Wrap the dough in wax paper and refrigerate it for 1 hour to overnight.
When ready to finish the cookies- Divide the dough (I divided mine into ⅓'s due to my small working space), and roll it to ⅛ inch thickness on a floured surface.
Cut into shapes with cookie cutters.
Place on ungreased cookie sheets, and bake in 375° F oven for 10-12 minutes.
Allow to cool 1-2 minutes, and then remove to wire racks to cool completely.
Decorate with your favorite frosting, sprinkles, candies, etc.