Use a knife or a lemon zester to remove the very outside oily skin from two oranges, and trim it into fine strips. Cut the skin and pith from all oranges and slice horizontally. Arrange in a serving bowl.
Place the sugar, half the water and the cinnamon stick in a small pan and stir over a medium heat until the sugar dissolves.
Leave the pan, without stirring, to simmer gently until the sugar turns a deep caramel. Carefully take out the cinnamon stick, remove pan from the heat and hold over the sink. Standing clear to avoid any spitting, carefully add the remaining water. Stir to remove any lumps of caramel.
Pour three-quarters of the caramel over the orange slices. Simmer the strips of zest in the remaining caramel for two minutes and spoon it over the fruit.
