Mix the water and sugar together in a small saucepan then bring it to a boil over medium heat and let simmer until it turns a medium amber colour.
Remove from heat then carefully pour in the cream while stirring. Continue to stir until it is smooth. Return it to heat if any lumps have formed, this will help melt them to get the smooth consistency.
Stir in the butter the allow to cool for a few minutes and stir in the vanilla essence and salt if using.
Dip the apples in whole or cut into slices and dip.