In a saucepan, combine water, passion fruit puree, sugar, salt, and butter. Bring to a boil, then reduce heat to low and add flour. Stir continuously until the mixture forms a smooth ball and pulls away from the sides of the pan.

Remove the dough from heat and let it cool slightly. Transfer to a mixing bowl, add the egg, and mix until smooth and glossy.

In a deep fryer, heat vegetable oil to 350°F (175°C).

Transfer dough to a piping bag with a large star tip. Pipe 4-6 inch strips of dough into the hot oil, using scissors to cut dough. Fry until golden brown, about 2-3 minutes per side.

Remove churros with tongs and drain on paper towels. Serve warm with a dusting of powdered sugar or a passion fruit dipping sauce.