A delicious twist on shortbread that is easy and melts in your mouth.
Cream the butter and sugar with a stand mixer, or use a handheld mixer/mash by hand. Don't worry if it is still a little grainy but it should be well mixed and have a slight sheen.
Add flour, corn starch/cornflour and orange zest and mix together so the zest is well distributed and dough comes together, but be careful not to overmix.
Press the dough into a log, approx 1 1/2in/5cm diameter, wrap in cling wrap/film and refrigerate for around an hour, or up to 3 days.
Shortly before ready to bake, preheat over to 350F/180C.
After chilling, carefully slice the log of dough into relatively thin slices (approx 1/4in/6mm) and place on a lined baking sheet with a little space between them.
Bake for around 10-12min until the cookies look dry and are just about starting to brown. Allow to cool a minute before transferring to a cooling rack.
Once cookies are completely cool, melt the chocolate in a small bowl (either over boiling water or in microwave in 30 second bursts, stirring in between). Dip the cookies into the chocolate one at a time, approximately a third to half the way in. Let excess chocolate drip off then lay on a cookie sheet or parchment to set. Repeat until all are coated, re-melting the chocolate as needed.