Try this easier, lighter version of the traditional chocolate yule log.
Beat eggs on high speed until very thick and lemon-colored. (If eggs are not beaten enough, cake will be heavy and rubbery.) Gradually beat in sugar. On low speed, beat in water and vanilla. Add dry ingredients gradually, beating just until smooth.
Pour into a heavy jelly-roll (10x15-inch) pan lined with greased and floured foil. (Fit foil snuggly into pan.) Bake at 375 degrees F for 12 to 15 minutes. Immediately loosen cake from edges of pan and invert onto a clean towel that has been sprinkled with cocoa. Carefully peel foil from cake. Trim edges of cake if necessary. While cake is hot, roll both cake and towel, starting with the narrow end, and place on wire rack, seam side down. Cool for at least 30 minutes.
Whip cream with vanilla and confectioners’ sugar. Unroll cooled cake and remove towel. Spread half the filling over cake, being generous at edges. Roll up. Spread remaining whipped cream over the log and sprinkle with cocoa.