In a medium bowl, sift together flour, baking soda, salt and spices. Set aside.
In a large bowl, by hand (or with an electric mixer), cream the butter until it is light and fluffy. Add the sugar and mix again until light and creamy. Blend in the eggs one at a time and then the molasses. Add the flour mixture in two additions either by hand or on low speed. The dough should be easy to handle, and not overly tacky. If needed, add more flour, one tablespoon at a time, until it isn't overly sticky. Divide the dough into two pieces, wrap each in plastic and chill for an hour or so.
Heat oven to 350F degrees, racks in the middle, and line a couple baking sheets with parchment paper. Set aside.