Preheat oven to 180ºC . Prepare a bundt pan. Sprinkle soda on prunes. Pour boiling water over and allow to cool. Cream butter and sugar in food processor. Add eggs. Add prune mixture and whir about 15 seconds. Add flour sifted with cocoa. Mix till blended with on/off motion. Pour into pan. Bake 45-55 minutes. When cool, turn out. Sprinkle with icing (powdered) sugar if you like. This is a deliciously moist cake. ----