Cooking the livers to medium/medium-rare in this recipe is key to a moist and rich tasting spread. Overcooking them will make the finished dish dry and crumbly.
- 5 tablespoons schmaltz (chicken fat) or unsalted butter, divided
- 3 medium yellow onions, sliced
- 2 tablespoons white wine vinegar
- 1 pound chicken livers, rinsed, patted dry
- Kosher salt, freshly ground pepper
- 1 tablespoon prepared horseradish
- ½ teaspoon mustard powder
- Toasted rye bread and sliced red onion (for serving)
Cook eggs in a saucepan of boiling water 10 minutes. Transfer to a bowl of ice water to cool. Peel eggs.
Meanwhile, heat 3 Tbsp. schmaltz in a large skillet over medium heat. Cook yellow onions, stirring often, until caramelized and very soft, 14–18 minutes. Add vinegar and toss to coat. Let cool. Wipe out skillet and reserve.
Season livers with kosher salt and pepper. Heat remaining 2 Tbsp. schmaltz in same skillet over medium-high. Cook livers until browned on both sides but still pink in center, about 2 minutes per side. Transfer to a plate and let cool.
Pulse half of livers, half of cooked onions, and 1 ½ eggs in a food processor just until a coarse purée forms. Transfer to a medium bowl. Repeat with remaining livers, onions, and eggs. Stir horseradish, garlic powder, mustard, and paprika into chopped liver; season with kosher salt and pepper.
Serve chopped liver on bread topped with red onion and seasoned with sea salt and pepper.
Do Ahead: Chopped liver can be made 3 days ahead. Cover and chill.