Soak liver in milk for approx. 1 hour before cooking, if you want to remove some of the bitterness. Pat dry before placing in the skillet.
Cook
Heat oil in skillet. Test temperature of oil with end of wooden spoon. When you see small bubbles surrounding the spoon, then you know the oil is hot enough and ready to use.
Add shallots, garlic, salt, pepper, Provencal herbs and sumac to the skillet. Mix ingredients together, making sure to move the shallots around the pan so they don't burn.
Remove shallots from oil when crispy golden to dark brown in colour and transfer to kraft paper or newsprint to absorb excess oil. Leave remaining oil in skillet to cook the liver.
In skillet, place liver and cook on one side at high heat for 3-4 mins or until edges have darkened. Then flip over onto other side and cook for 2-3 mins. Remove from skillet and let the liver rest for 3-5mins.
Slice liver into 1.5 inch strips and serve with crispy shallots on top.
Notes
This recipe works better with veal or calf's liver. If you're using chicken liver, pre-soaking in milk is not optional and reduce the cooking time of the liver by 1-2 mins.Chicken liver cooks faster and doesn't caramelize the same way as veal liver does.