Preheat oven to 170oC

Line tray with baking paper

Mix melted butter and sugar in a bowl

Add egg and vanilla then mix again

Gradually add flour, cocoa powder and baking soda then mix again

Mix in the chocolate chips then divide the dough into 8 and place onto the tray (4 per tray so spaced out enough to expand)

Slightly flatten each batter ball and bake for 8-10mins

Remove from oven and allow to cool for 30mins. They will be far too soft to handle at first and will harden when cooling

Store in an airtight container for up to 1week