In a large skillet, heat the chicken fat or oil over medium heat. Add the onion, pinch salt and pepper, reduce to low and cook for 30 minutes, stirring regularly.
Transfer the chicken livers and onions to a food processor. Add the hard-boiled eggs and pulse until the mixture is smooth and has the desired consistency. Alternatively, place livers on a cutting board and with a large chefs knife finely chop by hand, place in a bowl. Grate eggs over top, add onions and any remaining oil from pan and mix well.
Season the chopped liver with salt and pepper to taste.
Serve the chopped liver on its own or with crackers or bread. It can also be used as a filling for sandwiches or as a topping for matzah. Enjoy!
Chopped liver will keep covered in the refrigerator for 5 days.