In a small bowl, combine flour, cinnamon, baking soda, salt, allspice and ginger. Mix well and set aside.
Beat together butter, brown sugar and molasses with a mixer for 3 minutes, scraping down the sides halfway through mixing.
Add vanilla and eggs and beat well.
Add dry ingredients and mix just until combined.
Fold in chocolate chips and orange zest.
Using a 2 tablespoon portion scoop, scoop batter onto rounds wax paper. Place into the refrigerator for 1 hour.
Preheat oven to 325 and place dough, 2" apart on a parchment paper lined baking sheet and bake for 12-14 minutes or until edges are firm. Remove from oven and let stand to cool on baking sheet for 2 minutes before moving to a cooling rack to cool completely.
Once cookies are cool, mix together powdered sugar and milk until you have a glaze consistency that will fall off a spoon but isn't too thin that it barely sticks onto the spoon. Drizzle on top of cookies and let stand to harden.