This chopped liver recipe from Josh Russ Tupper of Russ and Daughters is used to make his popular Oy Vey Schmear sandwich.
Rinse livers under cold water to remove blood; drain. Heat a medium skillet over medium-high heat and add schmaltz and 2 tablespoons vegetable oil. Add caramelized onions. Cook, stirring, until beginning to brown, about 3 minutes.
Add livers to skillet and season with salt. Cook, stirring, until livers begin to brown and insides are pink throughout, 15 to 20 minutes. Transfer livers to a plate to cool slightly, about 10 minutes.
Meanwhile, in a small skillet, heat remaining 2 teaspoons vegetable oil. Add chopped onions and cook, stirring, until golden brown; remove from heat and set sauteed onions aside.
Place cooled livers and caramelized onions in the bowl of a food processor; pulse until well combined. Transfer to a medium bowl. Stir in hard-boiled eggs, sauteed onions; season with salt and pepper. Refrigerate at least 3 hours before using.