Pour 3/4 of a full shot of absinthe in a sundae glass. put a brown sugar cube on a spoon with holes in it and rest it on the rim of the sundae glass. Pour the remaining 1/4 of the shot of absinthe onto the brown sugar cube, light the brown sugar on fire (put the flame under the spoon). Let the flame burn for a minute while the brown sugar drips into the glass and caramelizes. stir the caramelized sugar into the glass. Add the water to the glass, stir again. and serve.