Preparation Bring 2 inches of water with 2 teaspoons salt to a boil in a 2-quart heavy saucepan. Add chicken and poach at a bare simmer, partially covered, until just cooked through, 12 to 14 minutes. While chicken poaches, whisk together lemon juice, honey, and 1/2 teaspoon salt in a bowl until honey and salt have dissolved. Whisk in shallot and oil, then whisk in apple. Divide lettuce, grapes, walnuts, and celery between 2 plates and drizzle with half of vinaigrette. Slice chicken and put on top of salads, then drizzle with remaining vinaigrette.
Preparation Bring 2 inches of water with 2 teaspoons salt to a boil in a 2-quart heavy saucepan. Add chicken and poach at a bare simmer, partially covered, until just cooked through, 12 to 14 minutes. While chicken poaches, whisk together lemon juice, honey, and 1/2 teaspoon salt in a bowl until honey and salt have dissolved. Whisk in shallot and oil, then whisk in apple. Divide lettuce, grapes, walnuts, and celery between 2 plates and drizzle with half of vinaigrette. Slice chicken and put on top of salads, then drizzle with remaining vinaigrette.