Do lamb kidneys require their cores to be removed and what is the easiest way to remove them? I am cooking lamb kidneys by frying them on a pan. If I do not remove the cores of the kidneys, that tissue in the core remains and is hard to chew afterwards. 

Is there a way to cook the kidneys with the cores in place so that they become softer? this is because they are not easy to remove.

What is the easiest technique for removing the cores if needed?
The simplest way to remove kidney cores is to cut the kidneys in half (horizontally) then snip the cores out with a pair of sharp scissors. With practice this can be done in two or three quick cuts.