How to Make It
Fry the bacon until crisp. Reserve the fat. Drain the bacon on paper towels and then crumble. Pour the bacon fat into a measuring cup and add enough oil to make 1/3 cup. Set aside.
In a large nonstick frying pan, heat 1 tablespoon of the cooking oil over moderately high heat. Season the chicken livers with 1/4 teaspoon of the salt and 1/8 teaspoon pepper. Add half the livers to the pan and cook 2 minutes. Turn and cook until browned but still pink inside, about 2 minutes longer. Remove. Repeat with the remaining livers and 1 tablespoon of the cooking oil. Put in a warm spot.
Wipe out the pan. Add the reserved bacon fat to the pan along with the vinegar, the remaining 1/4 teaspoon salt, and 1/4 teaspoon pepper. Bring almost to a simmer.
In a large bowl, combine the lettuce, apples, onion, and all but 2 tablespoons of the bacon. Add the warm dressing and toss. Put the salad on plates and top with the livers. Sprinkle with the reserved bacon.