Sift or sieve the dry ingredients together, to mix them well and to remove any lumps.
Cream the butter and brown sugar until the mixture is light and fluffy, scraping down the bowl at least twice. Add egg, mix well, then add the molasses, again mixing very well. Add the dry ingredients and raisins, mixing slowly so the flour doesn’t fly all around the kitchen. Stop when the dough comes together and you see no streaks of flour.
Divide the dough into 2 or 3 pieces. With wet hands, shape each piece into a log about 1 1/2″ in diameter, about 12″ long. (Wet hands helps keep the dough from sticking to you)
Wrap the dough logs in waxed paper and chill for at least 2 hours, or up to a week. Unbaked logs may be frozen, double-wrapped, to prevent loss of moisture.
To bake: heat oven to 375˚ and line a cookie sheet with ungreased parchment paper. Put two logs on a single cookie sheet, leaving at least 3 inches between them, as they will spread. Sprinkle the tops of the logs with granulated or turbinado sugar.
Bake 17-18 minutes, until the bars are puffy but still soft in the center. Slide parchment with the bars right onto a cooling rack, then let cool completely.
When cool, cut the dough strips crosswise into bars, and store the cookies in an airtight tin.