Start by warming Nutella in a microwave-safe bowl for about 15-20 seconds, until pourable but not too hot. Set aside to cool slightly.

In a medium saucepan, combine water, unsalted butter, salt, and granulated sugar. Bring to a boil over medium-high heat, then remove from heat and stir in all-purpose flour until a smooth dough forms.

Allow the dough to cool for about 5 minutes, then add eggs one at a time, mixing thoroughly until smooth and slightly sticky.

Prepare the cinnamon-sugar coating by mixing granulated sugar and ground cinnamon in a small bowl. Set aside.

In a deep pot, pour enough vegetable oil to fill about 2 inches deep and heat to 350°F (175°C).

Transfer the churro dough to a piping bag fitted with a star tip. Pipe 4-6 inch strips of dough into the hot oil, cutting with scissors.

Fry churros for about 2-3 minutes on each side until golden brown and puffed. Remove and drain on paper towels.

While warm, roll churros in the cinnamon-sugar mixture until evenly coated and serve with warm Nutella dip.