There was an offer on veal kidney on the market and I bought some. Two went straight into the freezer and one was for a weekend meal.
I had been reading several recipes, and discussed it with my hairdresser as one does in France. What had caught my eye is that in several Italian recipes (for rognoni) the kidneys are first put in a bowl of water with some vinegar, then dried and sprinkled with flour.
The French just put the rognons in a skillet and then remove them to discard the first juices, before resuming cooking.