Step 1

Begin by preheating your oven to 160°C / 320°F. Grease a 20cm square cake tin with oil spray and line the sides and bottom with baking paper. Set aside.

Step 2

Add the butter and chocolate into a heatproof bowl and microwave for 20 seconds at a time, stirring each time until completely melted and smooth. Alternatively, you can melt these two ingredients together by placing the bowl over a saucepan of simmering water. (don’t let the bottom of the bowl touch the water.

Step 3

Add the whisked eggs and mix them into the chocolate/butter mixture. Then add the cocoa powder, salt, sugar, vanilla extract and flour and mix until well combined. Finish by adding the chocolate chips, fold through using a spatula. Pour the batter into the square baking tin and spread out evenly using a spatula. Bake for 25 minutes, take out of the oven and allow to cool completely before slicing up and serving.