Place the butter, milk (the 110ml), water, caster sugar, salt and vanilla extract into a saucepan. Bring it to the boil and stir it to help the butter melt
Once it boils, turn down to a low heat and tip in the plain flour. Stir it well until the flour is combined and you have a soft dough that comes away from the sides of the pan
Place the dough into the bowl of a stand mixer. Spread it out a bit up the sides, this will help it cool. Cool for 10 minutes
While it is cooling, prepare your cinnamon sugar by mixing the caster sugar and cinnamon together in a wide tub. Get your oil ready for frying by adding it to a deep pan (or deep fat fryer) and heating it up. Also prepare a plate or tray with kitchen roll on it, and a baking tray lined with baking paper
Add the eggs and milk (the 1 ½ tbsp) to the churro dough and mix in your stand mixer using the paddle attachment until combined and the dough is smooth
Put the dough into a piping bag (double bag it if your piping bags are fairly thin) fitted with a closed star nozzle. I used a Jem 1E nozzle
Once the oil reaches 180C (350F) it is ready. You can test it by adding a chunk of bread to it and it should sizzle immediately
Pipe the churro dough directly into the hot oil. Pipe them about 5 or 6 inches long, then snip the dough with some lightly greased scissors or a knife
Pipe 3 or 4 churros into the hot oil at one time. Don't over crowd the pan. And don't worry, they won't stick together
Fry until golden brown, turning them as needed with a slotted spoon or spider strainer
When they are done, remove them from the hot oil using a slotted spooner or spider strainer, and place them onto the pre-prepared plate lined with kitchen roll. Pipe more churro dough into the hot oil. Then roll the cooked churros in the cinnamon sugar, use a spoon to help fully coat them
Place the coated churros on the pre-prepared baking tray lined with baking paper. Then check on the churros in the hot oil. Keep repeating this process until the churro dough is all used up
To make the chocolate sauce melt the dark chocolate and double cream together in a glass bowl in the microwave for 30 seconds, followed by 10 second bursts until fully melted together, stirring in between
Serve immediately, leftovers will keep in an airtight container for 2 days in a cool place. But they are best fresh! The chocolate sauce can be kept in the fridge and reheated as required