Preheat oven to 375 degrees F (190 degrees C). Sift together the flour, baking soda and salt into a small bowl; set aside.
In a large bowl, cream together the butter, shortening, white sugar and brown sugar until smooth. Beat in the eggs one at a time, then stir in the vanilla and milk. Gradually stir in the sifted ingredients using a wooden spoon. Finally, mix in the chocolate chips and crystallized ginger. Use two spoons to drop cookie dough 2 inches apart onto a cookie sheet.
Bake on the middle rack of the preheated oven for 12 to 15 minutes. The cookies should be golden brown on the sides and the top should have lost it's shine. Allow to cool on the baking sheet for a few minutes before removing to a wire rack to cool completely.