Lamb’s Fry is a dish that can include all offal from the lamb, e.g organs such as heart, liver and lungs.
It is eaten in Italy and northern England.
In northern England and the southern US, it means particularly the testicles.
In New Zealand and Australia, it means particularly the liver.
In any event, whatever part of the lamb you are being served, it’s fried up, either whole or cut into pieces.