Preheat oven to 350°F; lightly oil an 8-by-8-inch baking pan or coat with non-stick spray. Line bottom of pan with parchment paper or wax paper. Oil or spray paper.
Sift together flour, sugar, cinnamon, ground ginger and salt into a mixing bowl. Add crystallized ginger and stir to coat.
In another bowl, stir baking soda into hot coffee and whisk in molasses, egg white and oil. Pour into the dry mixture; stir JUST UNTIL BLENDED. Do not overmix or the cake will be tough.
Scrape the batter into the pan and bake 30-40 minutes, or until cake tester inserted in the center of the cake comes out clean. Cool in the pan for 5 minutes. Turn the cake onto a wire rack and cool until lukewarm.
Sprinkle the cake with confectioner's sugar or lay a stencil or paper doily on the cake and dust with sugar. Carefully remove the doily or stencil.