Sift the flours into one bowl.
Place water and butter in a small saucepan. Cook over medium-low heat until the butter has melted and the mixture comes up to the boil.
Working quickly, remove the saucepan off the heat, add sifted flours, place back on the heat and mix vigorously with a wooden spoon until the mixtures forms a dough ball.
Transfer pastry ball into a clean bowl. Add egg and whisk together until the pastry is smooth and lightly glossy.
Transfer pastry into a piping bag, twist the end of the bag, squeezing mixture gently into the nozzle.
Heat olive oil in a small, shallow saucepan or frypan over low heat - the oil level should only be about 2cm or 1inch deep, until just starting to smoke.
Squeeze choux pastry logs into the hot oil, about 5cm or 2inches long, cutting off each churro log with pair of kitchen scissors.
Fry 4 to 5 at a time, for about 20 seconds on each side, or until golden brown.
Remove from oil onto paper towel using metal tongs.