Check that the purchased liver is fully cooked and ready to eat; if it is only partially broiled or labeled for further cooking, cook it according to the package instructions before proceeding.

Heat the oil in a skillet and fry the chopped onion until evenly golden. Remove the onions with a slotted spoon, reserving the onion-flavored oil separately.

Place the prepared liver in a food processor and process first until broken down.

Add the drained golden onions and five hard-boiled eggs. Process until combined. Add the sixth egg only if a milder, eggier taste is desired.

With the processor running, add the reserved onion oil a spoonful or two at a time. Pause to check the consistency, continuing until smooth and creamy like pâté. The amount of oil depends on how moist the liver is; do not force in a fixed quantity.

Season with salt and black pepper to taste. Transfer to a shallow covered container and refrigerate promptly. Serve chilled.