Though ginger gets star billing, I've always felt that it's molasses that makes gingerbread so distinctive. Made from refined sugar cane, molasses not only gives gingerbread its deep, rich flavor and dark color, but it also helps keep the cake moist. Different recipes call for different spices, but I like the combination of ginger, cinnamon, and cloves. Ground spices lose their fragrance within a few months. Creamed cakes rise because air is beaten into the butter when it's creamed with the sugar.
Blended cakes rely on chemical leavens.
In this recipe, I start with creamed butter for the texture and of course for the flavor it gives. But adding the heavy molasses to the batter deflates some of the air that's been beaten into the butter, so I add baking soda to make sure that the cake has a light, porous texture. At this temperature, it's pliable enough to trap air into the batter. Make blending easier and the batter smoother by being sure that the eggs and molasses are also about the same temperature. Because molasses is slightly acidic, this recipe calls for baking soda.