Heat up about 4 tablespoons of the butter, along with a small dash of oil to the skillet as well.
Add in the liver and then cook this for about 5 or so minutes, until this dish starts to brown.
Once this is finished cooking, put the onions directly onto the skillet, heating these up together with the liver as well.
Take the liver and onions and put this onto a plate. Use a stock and the wine to deglaze this, and from there, you want to make sure the liquid is reduced in this until it creates a nice, thick sauce that will really give you something to enjoy with this.
Take the liver, put it on a serving dish, and then, also add the onion to this. Add the sauce you just made, and then add a bit of parsley in order to garnish, and then you can serve it!
