In a large skillet, heat 2 tbsp of butter and the olive oil over medium heat. Add the onions and cook, stirring occasionally, until they are caramelized and golden brown, about 10-15 minutes. Remove the onions from the skillet and set aside.
In the same skillet, add the remaining 2 tbsp of butter. Once melted, add the liver slices and cook for 3-4 minutes on each side, or until browned and cooked through. Be careful not to overcook the liver, as it can become tough.
Return the caramelized onions to the skillet and heat through for another minute.
Serve the liver and onions hot, garnished with fresh parsley if desired.
Enjoy your Liver and Onions, a classic dish with rich and savory flavors!
