In a small bowl, whisk flour, baking powder, baking soda, salt, ground ginger, ground cinnamon, mixed spice together

In another bowl, beat butter, brown sugar and egg on medium speed until fluffy

Add molasses and vanilla and continue to mix well

Stir dry ingredients into wet ingredients until smooth

Divide dough into half and wrap each in plastic wrap and put in the fridge to set for at least 2 hours or overnight

Preheat oven to 375DegF. At the same time, prepare baking pans by lining with non stick baking paper or parchment paper

Roll dough btw 2 plastic wrap so it wont stick to the rolling pin until 1/4 inch thick

Cut out cookies with desired Christmas cookie cutter and place on baking sheet. Make sure each cookie is about 1-2 inches apart. 

Bake cookies for 7-10 mins. Remove from oven and let cool completely before decorating

In a mixing bowl, combine powdered sugar, egg whites and cream of tar tar

Mix until combined then add in vanilla and beat until icing is thick and sticky like white glue. 

Add in 1/2 tbsp of water and beat on high for about 2-3 mins

You can color the icing sugar to your desired color at this point in time

Make sure to place a piece of plastic wrap over the top of the icing to prevent a skin from forming if you are not using the icing immediately. 

Decorate cookies with icing and let dry for at least a few hours before packing them.