You can use either light molasses or dark molasses for this recipe. The light variety is sweeter and has a less bold flavor. The dark variety is more robust with a stronger flavor. Stay away from blackstrap molasses for this recipe. It is more bitter and works best in savory dishes.
Consider making a simple icing to drizzle over the tops of these cookies. Mix together 2 cups powdered sugar with 4-5 tablespoons milk until smooth.
Dark or brown sugar (or a combination of the two!) can be used here.