The secret of this recipe for classic Liver and Onions is the long, slow cooking.
Cook the onions at least 20 minutes, during which time they will develop a rich brown color and release their natural sweet taste.
Prepare the liver while the onions are cooking by cutting it into thin, even strips. By slicing the liver in this fashion you enable it to cook thoroughly in only about 3 minutes. The short cooking time gives the liver a velvety texture and helps it achieve the maximum flavor. Add a drop of vinegar or lemon juice at the end of the cooking time to further enhance the flavor.
Peel and quarter 2 large onions and slice thinly. In large skillet heat 2 tablespoons oil, then add onions and season to taste with salt and pepper. Cook, stirring occasionally, until onions are golden brown, about 20 minutes. Move onions to edge of pan, add 2 tablespoons oil and heat until hot.
Add 1 pound calf's liver, cut into strips, and cook, stirring constantly, about 3 minutes or until done. Sprinkle juice of 1 lemon over liver, then stir with onions. Sprinkle with 2 tablespoons chopped parsley. Makes 4 servings.