Step 1Heat the schmaltz or oil in a pan and add the onion. Cook over medium-low heat until softened, about 5 minutes.
Step 2Add the livers and cook until browned on the outside and medium rare on the inside, about 4 to 5 minutes. Add the sherry and reduce until almost evaporated. Add the chicken broth and let cook for a few minutes. Remove from the heat.
Step 3When slightly cooled, transfer the mixture to a food processor. Pulse 2 or 3 times to combine. Do not mix to a fine puree. It should be a little chunky. Remove to a mixing bowl.
Step 4Push the hard-boiled egg through a cheese grater and add to the liver mixture. Add the gribenes (chicken skin cracklings), if using, and add salt and pepper to taste.