Sift the flour and salt into a large bowl and make a well in the centre. Carefully pour in the water and whisk in until the mixture is completely smooth.
Pour the mixture into a saucepan and cook over a low heat, stirring constantly for two minutes. Remove from the heat, pour into a bowl and leave the batter to rest for one hour.
Heat the oil in a saucepan over a medium heat. Test the temperature of the oil by dropping in a teaspoonful of the mixture – if it turns golden brown within 30 seconds the oil is hot enough.
Spoon the mixture into a piping bag with a small nozzle. Pipe lengths into the oil and fry until golden brown on all sides. Do not overcrowd the pan, remove and drain on kitchen towel.
Dust generously with sugar and serve with hot chocolate.