Pat dry 1 pound chicken livers and season with salt and pepper. Cook in a skillet with 3 tablespoons chicken fat or olive oil, turning, 7 minutes; transfer to a food processor. Add 2 more tablespoons fat, 1 chopped onion and some fresh thyme to the pan and cook 8 minutes. Stir in 1/4 cup sherry and boil 1 minute; add to the processor along with 1 cup crushed saltines, 1 hard-boiled egg and 2 tablespoons fresh parsley. Pulse; season with salt and cayenne. Chill, then spread on crostini. Top with hard-boiled egg and radish slices.