Mix the sugar and cinnamon for the churros in a wide, shallow dish; this is for coating the cooked churros.
Churros: Put the flour into a bowl and stir in the baking powder, then beat in the olive oil and 1 cup freshly boiled water. Keep mixing until you have a warm sticky dough, and let rest for about 10 minutes or for as long as it takes for the corn oil to heat up.
Heat the oil in a smallish saucepan; it should come about a third of the way up the sides of the pan. When you think it's hot enough, toss in a cube of bread and see if it sizzles and browns. If it browns in about 30 seconds, it's hot enough; or if you're using an electric deep-fat fryer regulate the temperature, it should be at 325 degrees F. Keep a watchful eye on your hot oil pan at all times.
Preheat the oven to 175 degrees F.
When you are ready, load up a piping bag with a large star shaped nozzle (8mm) and fill it with the churro dough. Squeeze short lengths, approximately 1 1/2 to 2 inches, of dough into the hot oil, snipping them off with a pair of scissors as you go. Cook about 3 or 4 at a time. Once they turn a rich golden brown, fish them out with a slotted spoon or tongs onto a kitchen towel lined baking sheet. To keep the churros warm while you fry the remaining dough. Blot them with paper towels and transfer them to a parchment lined baking sheet. Put the baking sheet into the oven to keep the churros warm. Even if you let them sit out of the oven, they do need 5 to 10 minutes to rest before you eat them, to allow them to set inside.
Chocolate sauce: Melt all of the chocolate sauce ingredients in a heavy based saucepan over low heat. Once combined and the chocolate has melted, remove the pan from the heat and set it aside in a warm place.
Toss the hot churros into the sugar and cinnamon mixture and shake them about to get a good covering, just before serving. Arrange the churros on a serving platter and serve.
Pour the chocolate sauce into individual pots for serving (to avoid the double dipping dilemma) and dip'n'dunk away.
From Nigella Kitchen by Nigella Lawson. Copyright (c) 2010 Nigella Lawson. Published by Hyperion. All Rights Reserved.