EK is offering Kosher meal for years and they follow the sandart routine. FA will present the sealed box (with all the certificares and stamps) to the pax and will ask to open it and hand back the hot meal casserolle. Then FA heat the casserolle and serve it after 15-20 minutes to the pax.
On MEL-AKL flight I've seen a big group of jewish orthodox people dressed in the most conservative way, reading small religius books during the whole flight and all of them enjoyed the KSML served by EL