Churros with chocolate-custard sauce

This is my mum's and grandma's recipe. I remember standing on a chair watching my grandmother cook these and my girls, now, make it the same at home. These are shallow-fried in a pan of oil, so they keep their shape and make it easier to turn. For the dipping sauce, the consistency should be thick enough to cling to the churros, and it has to be silky smooth - my secret is custard powder. Make the sauce when you're ready to serve, as it does form a skin.