Heat oven to 350°F and arrange a rack in middle. Prepare a 9x5 loaf pan with butter, dust with flour or use baking spray.
Combine flour, ginger, baking soda, cinnamon, salt, allspice, cloves and nutmeg in a medium bowl. Whisk to aerate and combine; set aside. In a measuring cup, stir together buttermilk and vanilla until combined.
1 1/2 cups all-purpose flour, 1 tablespoon ground ginger, 1/2 teaspoon baking soda, 1 teaspoon ground cinnamon, 1/2 teaspoon salt, 1/4 teaspoon ground allspice, 1/4 teaspoon ground cloves, 1/4 teaspoon fresh ground nutmeg, 1/2 cup buttermilk, room temperature, 1 1/2 teaspoons vanilla extract
Combine butter and brown sugar in the bowl of a stand mixer fitted with a paddle attachment. Beat on medium speed until light in color and fluffy and forms small peaks, about 5 minutes.
1/2 cup unsalted butter, 3/4 cup packed dark brown sugar
Beat in molasses until well combined then add eggs, one at a time, beating after each addition until well incorporated.
1/2 cup blackstrap molasses, robust, 2 large eggs
Scrape bowl and paddle (mixture will look a little curdled). Add one third flour mixture beating on low speed just until flour is incorporated. Add half buttermilk mixture until it's smooth. Add another third of the flour mixture. Add remaining buttermilk and mix until incorporated. Turn off the mixer and hand stir the remaining flour mixture just until incorporated and smooth. DO NOT OVER MIX.
Pour into prepared pan.
Bake for 45 minutes, or until a toothpick inserted in the middle comes out clean and the cake is pulling away from sides of the pan.
Cool cake in pan for 10 minutes and then turn out onto a rack to cool completely.