Preheat oven to 350 F and grease a bundt pan (or 9 x 13-inch baking dish). Cream butter and sugar using an electric mixer, then beat in eggs one at a time. In a medium bowl, mix flour, ginger, allspice, baking soda, and salt. In a separate bowl, stir beer into molasses to dissolve. Alternately beat some of the dry ingredients and some of the beer mixture into the butter mixture until all are incorporated.
Pour into prepared pan and bake 30 to 35 minutes. Let pan cool on a wire rack for 10 minutes. Run a knife along the edges of the pan to loosen the cake, then turn out onto cake stand or platter. Let cool to room temperature before dusting with powdered sugar.
Per serving: 296 calories, 9 grams fat (5 grams saturated fat), 67 milligrams cholesterol, 342 milligrams sodium, 49 grams total carbohydrates, 1 gram fiber, 4 grams protein.
