glug of extra-virgin olive oil
knob of unsalted butter
2 onions, very thinly sliced
200g calves liver, thinly sliced
good dash of red wine
dash of beef stock
A few drops of white wine vinegar
Polenta to serve
Heat the olive oil with the butter in a large pan over a medium heat. Add the onions and cook them over low heat until they are very soft and slightly browned in colour but not burnt, for about 1 hour.
Dust the liver in flour.
Add the liver to the pan and cook quickly for about a minute.
Add the wine to the pan and scrape the bottom of the pan with a wooden spoon to dislodge any browned bits, then add the beef stock and stir for a few minutes.Once the liver is cooked through add chopped parsley stir for couple of seconds then plate up.
Drizzle the vinegar over and serve immediately with polenta on side.