Whisk flour, baking soda, salt, and spices.
Cream butter, ½ cup sugar, and brown sugar.
Beat in egg, molasses, and vanilla.
Mix in dry ingredients.
Chill dough for 1 hour.
Roll into balls, coat in remaining sugar, and flatten slightly.
Bake at 350°F for 8–10 mins. Cool completely.
Melt white chocolate with shortening. Dip half of each cookie.
Decorate with holly sprinkles.