For the vinaigrette, in a small bowl or small glass jar with a lid, combine the vinegar and shallot and let sit for 5 minutes. Add the oil, apple jelly, mustard, salt, and pepper and whisk until blended or put the lid on the jar and shake for about 20 seconds. (The vinaigrette will keep for three days in the refrigerator. Shake well before using.)

In a large bowl, toss the chopped romaine, arugula, radicchio, and sliced red onion. Divide among 4 plates or bowls and top each one evenly with the apple slices, chopped chicken, crumbled Gorgonzola, and pecans. Drizzle about 2 tablespoons dressing over each salad and serve.