One of my favourite treats is veal liver.
I chop an onion and caramelize it in butter, having seasoned it with salt and pepper. I use a very generous amount of butter. When heavily caramelized, I drain the butter (but reserve it), put the caramelized onions back in the pan and add some red wine or sherry vinegar. This helps to cut the richness. I plate the caramelized onion and quickly take a whole veal liver, lightly seasoned with salt and pepper, and sear it on both sides. I plate this on the bed of caramelized onions.
The richness of the veal liver - the soft texture, and its flavour - contrast well with the caramelized onions that have had their richness cut a bit with the red wine or sherry vinegar.
I love organ meat. Grilled rabbit liver is one of my favourites, too, but it is harder to come by in my area.