Use a fork to cream dairy-free butter, sugar and vanilla essence.
Add flour, cornstarch and salt.
Mix with a mixer (or simply using your hands) until crumbly consistency. Crucial to this recipe – do not overwork/overmix your batter.
Chop up chocolate and add to mixture.
Cover dough in cling film and set aside in fridge for 30 minutes. This will relax the gluten, preventing it from becoming chewy and tough.
Pre-heat your oven to 160°C/320°F (fan oven. Set to 180°C/356°F if you don't have a fan oven setting)
Roll out your dough until 1 cm thick and cut out your shortbread / cookie shapes with a cookie cutter.
Place biscuits on parchment paper, sprinkle with caster sugar and bake for 30 minutes.
Notes
Using the hand mixer is completely optional. You can do the job just as well by mixing the dough with your hands.
Don't have cling film? Simply place the dough into a bowl and cover the bowl with a moist towel instead.
Don't be tempted to roll out your dough too thin. This will make it more difficult to handle.
Don't have a cookie-cutter? Use a sharp knife to cut these into rectangle shapes instead. Alternatively, you could use the top of a small glass to cut out the round shapes.
30 minutes baking time might initially sound a little bit long for tiny biscuits, but this is needed because of the extra moisture present in dairy-free butter.