Adjust a rack one third up from bottom of oven and preheat oven to 180ºC . Butter a 10x 11 cm angel food tube pan (it may be a 1 piece non-stick pan) with an 18 cup capacity; butter pan even if it has a non-stick finish. Dust it all over with fine, dry bread crumbs, invert over paper and shake out excess crumbs and set the pan aside. Sift together the flour and baking soda and set aside. Cut the candied ginger into quarter to 1 cm pieces and set aside. Grate the fresh ginger and set aside. In the large bowl of an electric mixer, beat butter until soft. Gradually beat in the grated fresh ginger and 2.25 cups of the sugar (reserving the remaining half cup). Then, beat in the egg yolks. On low speed, gradually add the sifted dry ingredients in two additions, alternately with the sour cream in one addition. Remove the bowl from the mixer. Stir in half of the diced, candied ginger (reserve the remainder). Set aside. In the small bowl of the electric mixer (with clean beaters) beat the egg whites until they hold a soft shape. Reduce the speed to moderate and gradually add remaining half cup of sugar. Then increase the speed again and beat only until the whites hold a peak when the beaters are withdrawn. In three additions, fold the whites into the batter; with the first 2 additions, fold only partially, don't be too thorough and with the last addition, do not fold more than necessary to incorporate the whites. Turn into the prepared pan and smooth the top. Sprinkle the reserved candied ginger on top. Bake for about 1 hour, or, until a cake tester inserted gently into the cake comes out clean. (The cake will not rise to the top of the pan). Let the cake cool in the pan for 10 to 15 minutes. (The cake will sink about 3 cm as it cools). Then cover the pan with the cakeplate and, holding the pan the plate firmly together, turn them over and remove the pan and let the cake cool. This is a Maida Haetter recipe. *a piece 3 to 10 cm long and about 3 cm thick ----