Simmer under low heat for approximately seven minutes.
Beef kidneys like ox hearts should not be cooked "dry" ~ be it pan fry or extreme high heat or otherwise they'd pop all over. Instead, simmer with liquids as advised in the parent manuscript and within Glycation End Products accompanying manuscript.
To help reduce the typical "gamey" organ meats; use lemons, lime and aromatic herbs. Garlic powders and soy sauce work equally well to accompany as condiment.
Another basic recipe sans elaborate prepping.
Live-it-forward,
AW.