Calves Liver Veneziana
Slice thinly two medium onions and cook them over moderately high heat in 4TB unsalted butter and olive oil for about 15 minutes.
Salt and pepper thin liver slices. (Cook them as you buy them from the store. It's too hard to turn them if you slice them crosswise, the real Venetian way.) Sometimes try dusting them in flour, but this isn't necessary.
Turn the heat back up to hot and saute the liver VERY quickly, about two minutes on each side. Quick cooking is crucial for liver.
Add Balsamic vinegar (a little) and red wine (more) to deglaze pan. Throw in a dash of sugar.
Serve with polenta.