Step 1

Preheat oven to 220°C/200°C fan-forced. Line 2 large baking trays with baking paper.

Step 2

Make basic choux pastry: Combine butter and 2/3 cup cold water in a saucepan over medium heat. Cook for 3 to 4 minutes or until butter has melted and mixture just starts to boil.

Step 3

Reduce heat to low. Add flour. Cook, stirring, for 2 to 3 minutes or until mixture comes away from side of pan and forms a ball. Set aside for 5 minutes to cool slightly.

Step 4

Reserve 2 teaspoons egg. Using a wooden spoon, gradually beat in remaining egg until well combined and mixture forms a glossy dough (mixture should drop from the spoon).

Step 5

Spoon dough into a piping bag fitted with a 1cm plain nozzle. Pipe 12cm long logs, 6cm apart, onto prepared trays. Brush with reserved egg.

Step 6

Bake 1 tray of eclairs for 5 minutes. Reduce heat to 180°C/160°C fan-forced. Bake for 8 to 10 minutes or until golden and puffed. Using a small knife, carefully cut eclairs in half horizontally. Return to oven, cut-side up. Bake for 5 minutes to dry out centres. Cool on tray. Increase temperature to 220°C/200°C fan-forced. Repeat with remaining tray.

Step 7

Using an electric mixer, beat cream, vanilla and sugar until firm peaks. Place chocolate and butter in a microwave-safe bowl. Microwave on medium-high (75%) for 1 to 2 minutes or until smooth, stirring every 30 seconds.

Step 8

Spoon cream into a piping bag fitted with a 1cm fluted nozzle. Pipe cream evenly over eclair bases. Spread tops with chocolate mixture and place over cream. Refrigerate for 20 minutes or until chocolate has set. Serve.