Step 1

Preheat oven to 190°C. Line a 5cm deep, 18cm (base) square cake pan with non-stick baking paper.

Step 2

Heat butter, chocolate and sugar in a saucepan over low heat, stirring constantly, until melted and smooth. Transfer to a heatproof bowl. Set aside to cool slightly.

Step 3

Add eggs and vanilla to chocolate mixture. Mix well. Sift flour and cocoa over chocolate mixture. Stir to combine.

Step 4

Pour brownie mixture into pan. Bake for 20 minutes or until just set. Set aside to cool. Once cooled, lift out. Wrap in plastic wrap. Place into an airtight container. Stand for 1 day. Cut into pieces. Serve.