Pour the water and milk into a saucepan and add the butter, then place on the heat and bring to the boil. Sieve the flour into a bowl. Remove the saucepan from the heat then add the flour. Place over a very low heat and stir vigorously with a wooden spoon until the mixture leaves the side of the saucepan and forms a smooth ball, this should take about 3-5 minutes.
Transfer the mixture to a bowl and then, straight away, add the eggs one at a time beating thoroughly after each addition, beat until smooth and glossy. Allow to cool slightly for 5 minutes before placing into a piping bag.
Fill a piping bag with the mixture and using a large nozzle pipe walnut size pieces onto a parchment lined baking tray. Continue until all the mixture has been used. Gently brush with a little egg wash then place into the oven for 35-40 minutes until they are golden brown. Leave to cool on a rack.
Meanwhile, prepare the chocolate sauce. Bring the cream to boil then remove from the heat. Place the chocolate pieces into a bowl then pour half the boiling cream over the chocolate, stir to combine, then add the remaining cream (this will avoid the mixture splitting). Stir until smooth, then keep warm until required covered with a layer of clingfilm.
Before serving, cut the choux pastries in half and fill them up with whipped cream (or ice cream), this is normally piped into the choux but if under time constraints this works for me!
Place the filled choux onto a serving plate and drizzle each a little of chocolate sauce. Enjoy!