- 1 1/4 pounds skinless boneless chicken breast halves (about 3)
- 3/4 cup finely chopped celery
- 1/2 cup plus 3 tablespoons mayonnaise
- 1/4 cup finely chopped red onion
- 2 tablespoons chopped fresh tarragon
- 2 tablespoons fresh lemon juice
- 1 teaspoon grated lemon peel
- 12 slices rye bread with seeds
- 2 cups thinly sliced romaine lettuce
- Bring large saucepan of salted water to boil. Add chicken breasts; reduce heat to medium-low, cover and simmer until chicken is just cooked through, about 12 minutes. Transfer chicken to plate; cool.
- Mix celery, 1/2 cup mayonnaise, onion, tarragon, lemon juice, and lemon peel in large bowl to blend. Cut chicken into 1/2-inch cubes; stir into mayonnaise mixture. Season with salt and pepper. (Can be made 4 hours ahead. Cover; chill.)
- Arrange 6 bread slices on work surface. Spread with 3 tablespoons mayonnaise. Divide salad among bread slices. Top each with lettuce and second bread slice. Cut sandwiches in half and serve.