Add 250 ml water, 20 g caster sugar, and 25 g butter to the saucepan. Bring the mixture to a rolling boil over medium-high heat.

Add all 140 g all-purpose flour and 1/4 teaspoon baking powder at once. Stir vigorously until a cohesive dough forms.

Cover the saucepan with the lid. Steam the dough off the heat for 2 to 3 minutes.

Stir the remaining 15 g butter into the warm dough. Transfer the dough onto the silicone mat.

Knead the dough briefly until smooth. Avoid overworking it while it is still warm.

Fit the piping bag with the star nozzle and fill it with dough. Pipe ridged churro lengths onto the silicone mat.

Heat vegetable oil in the deep frying pan to about 180°C / 355°F. Carefully pipe or place the churro dough into the hot oil.

Fry the churros for 3 to 4 minutes until golden brown. Turn them as needed for even browning.

Lift the fried churros from the oil with the slotted spoon. Drain them briefly on the plate.

Combine 50 g granulated sugar and 2 g ground cinnamon in the mixing bowl. Toss the slightly cooled churros in the cinnamon sugar.

Serve the cinnamon-sugar churros warm. Offer 100 g Nutella as a dipping sauce.