(Soak bread in a bowl with water and squeeze well. If you have fresh white bread, not necessarily.) Beat the toe in the mixer bowl with two tablespoons of oil (for not to stick) for 5min. and add grated and well drained onion.
Add bread little by little and continue processing, until the ingredients become one regular mass. Start adding the oil little by little and the lemon juice.
Once you add all the oil and lemon juice, try if it needs more oil or lemon juice. Put the fish roe salad in a bowl and sprinkle with parsley. Cover the bowl and keep in refrigerator.