Sift the flour, baking powder and sea salt together in a large bowl and mix well. In a large saucepan, heat 250ml (8½fl oz/1 cup) water and butter until just boiling. Lower the heat, tip in the flour mixture and beat together quickly until you have a stiff dough that comes away cleanly from the sides of the pan. Tip the dough back into the bowl, spread it thinly around the sides and leave it to cool for 5 minutes.
Meanwhile, in a separate bowl, mix together the sugar and cinnamon. Set aside.
One at a time, beat the eggs into the cooled dough, mixing until fully incorporated before beating in the next. You may need to use a whisk in conjunction with a wooden spoon – the mixture will come together eventually.
Cut the tip from a piping bag and fit the star shaped nozzle. Spoon in half of the prepared dough and set aside to rest for at least 10 minutes.
Heat the oil in a large saucepan, making sure to fill it no more than two-thirds full, and bring the temperature up to 180ºC/350°F. While the oil is heating up, in a separate, small saucepan heat the cream with the chilli powder. Just as it begins to boil, lower the heat and add the chopped chocolate. Stir continuously until the chocolate has melted. Turn off the heat, cover and keep the sauce in a warm place.
Preheat your oven to 50ºC/120°F. Once the oil has reached the correct temperature, carefully pipe hoops of dough straight into the hot oil, using the side of the pan to ‘cut’ the end of each hoop. It’s best to cook just three to four churros at a time as they’ll cook more evenly. Fry the churros for 1½–2 minutes on each side, until golden-brown and evenly crisp all over. Use a slotted spoon to transfer the churros one by one to a plate lined with kitchen paper, carefully draining the excess oil into the pan beforehand.
Toss the churros in the bowl with the cinnamon sugar within a minute of removing them from the pan, and keep the sugared churros in the oven to keep warm.
Repeat, until you have used up all the dough, and serve the churros hot with the chocolate sauce to dip.
Alphabet Cooking: M is for Mexican (Quadrille, £12) Photography Kim Lightbody
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