Put the flour, sugar and cocoa in a large bowl and stir well.
Cube the butter and add to the bowl.
Rub the mix through until you get an even crumb.
Add the vanilla extract and a tbsp of cold water, then cut it through the mix with a round knife.
Eventually, you should be able to work the mix into a soft dough. You can add a drop more water if necessary.
Turn the dough out on to a floured surface β itβs a bit too squidgy, wrap and chill it for 10 minutes
Roll the dough to 1cm thick β I like to do this between two sheets of baking paper as it avoids sticking. Alternatively, you could lightly flour your work surface.
Cut out your biscuits using a round 7cm cutter. Gather up the offcuts and keep cutting until you have around 15 rounds.
Place the rounds on baking tray lined with baking paper and press a few chocolate drops into each one.
Bake for 12-15 minutes until just firm when pressed. When cool enough to handle, transfer to a wire rack to cool completely!
Once cool, enjoy on their own, with a cup of tea, or dunked into a glass of ice cold milk.
Video
Notes
Once your chocolate shortbread has completely cooled, place it in a tin or other airtight container to keep it as fresh as possible.