Bring 600ml (1 pint) water, the oil and salt to the boil ina roomy saucepan. As soon as it's bubbling, beat in the flour a fistful at a time until you have a smooth soft dough nall which leaves the sides of the pan clean. Allow to cool.
For the homely version - leave the fancy piping to the professionals - pack the dough into a large star-shaped piping-syringe, the kind you'd use for a biscuit dough. The opening should be about as wide as your thumb. Lay a clean cloth on the table and dust it with flour. Pipe out half a dozen finger-length churros - don't do them all at once or they'll form a skin and burst when they encounter the hot oil.
Meanwhile, heat a deep pan of frying oil - this is one of the moments when the Spanish cook reaches for the deep-fryer. When the oil is good and hot and lightly hazed with blue, slip in the first batch of churros and fry until golden. If the oil is too hot, the centres will remain raw. If too cool, the churros will break up in the oil. Transfer to kitchen paper and drain.
While the first ones are cooking, pipe out another half-dozen lengths and transfer them to the oil. Continue until all are done. Practice makes perfect. Hand the sugar around separately (people who like to dunk their churros in their morning coffee or hot chocolate usually sweeten the drink rather than the churro).
If you'd like to try a potato dough, replace half the flour with mashed potato. Potato churros are always ridged, short and thick.