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.