Line one baking sheet with parchment paper and fit a piping bag with the star piping nozzle.

Heat the water, granulated sugar, butter, sea salt, and vanilla extract in the saucepan over medium-high heat until boiling.

Add all of the wheat flour to the boiling liquid and whisk vigorously until a smooth dough forms.

Cook the dough while stirring until it pulls away from the sides of the saucepan.

Transfer the dough to the large bowl and let it cool until warm to the touch.

Add the egg to the warm dough and whisk until fully incorporated.

Fill the prepared piping bag with the churro dough and pipe 12 to 15 sticks onto the lined baking sheet.

Freeze the piped sticks until semi-frozen and firm enough to lift without losing their shape.

Heat the neutral frying oil to 350 °F (177 °C) in the saucepan and check the temperature with the kitchen thermometer.

Fry the semi-frozen churro sticks in batches until golden brown, about 3 to 4 minutes per batch.

Transfer the fried churros to the wire rack set over a baking tray and allow excess oil to drain.

Coat the warm churros with all of the cinnamon sugar.

Fit the second piping bag with the round piping nozzle and fill it with the Nutella hazelnut cocoa spread.

Pipe the Nutella hazelnut cocoa spread over the coated churros and dust with icing sugar.

Serve the churros with strawberries and whipped cream while warm.