Step 1

Preheat oven to 220C. Line two baking trays with baking paper.

Step 2

Spoon or pipe 16 balls of choux pastry onto trays, allowing room for spreading. Bake for 10 minutes.

Step 3

Reduce oven temperature to 200C and bake for 15 to 20 minutes, swapping trays after 10 minutes, or until choux pastry is puffed, golden and firm to the touch.

Step 4

Remove from the oven and allow to cool completely on trays.

Step 5

Filling: Whisk egg yolks, sugar and vanilla in a bowl, and stir in cornflour and flour.

Step 6

Add milk, ¼ cup at a time, stirring well after each addition.

Step 7

Transfer to a saucepan and cook, stirring constantly, over medium heat for 10 to 12 minutes or until mixture comes to the boil. Boil, stirring constantly for 1 minute.

Step 8

Pour custard into a heatproof bowl, and cover surface with baking paper.

Step 9

Allow to cool.

Step 10

Chocolate sauce: Combine freshly brewed strong coffee, whipping cream and chocolate in a heatproof bowl.

Step 11

Microwave uncovered on high for 2-3 minutes, stirring every minute with a metal spoon until melted and smooth.

Step 12

Cut pastries in half using kitchen scissors, then fill bases with custard.

Step 13

Replace tops and spoon over warm chocolate sauce.