In a saute pan over medium heat, melt butter and add brown sugar. Add the banana pieces and allow to brown on both sides.
In a small bowl combine the sour cream and the confectioners' sugar.
To assemble, place crepe on plate and thinly spread with banana mixture. Thinly spread dollop of sour cream mixture and sprinkle with toasted almonds. Wrap crepe tightly to create rolled layers. Dust with confectioners' sugar and sprinkle with crushed toasted almonds.
In a blender place water, milk and eggs and mix. Add sugar, salt, flour and butter. Mix until smooth. Let batter rest for 30 minutes.
Heat a seasoned crepe pan over medium heat. Ladle 1-ounce batter into pan and angle pan so that batter spreads to edges of pan. Let cook about 45 seconds and turn over. Cook about 30 seconds more. Remove to cool. Stack between sheets of waxed paper.