Poaching chicken in a flavorful broth produces moist, tender meat.
Place chicken, carrots, onions, celery,bay leaf, parsley, wine, and peppercorns ina stockpot. Add water to cover (about 3quarts); bring to a boil. Reduce heat soliquid is at a bare simmer. Poach, adjusting heat to maintain bare simmer andskimming any scum off the top, untilchicken is cooked, 20 to 25 minutes.
Remove chicken from stock; use a sharpknife to remove meat from bones. Placemeat in a dish; add stock to just cover. Return bones to pot; simmer until very flavorful, about 1 hour. Pass stock through a cheesecloth-lined strainer; discard solids.
In a clean saucepan, return stock to aboil. Reduce heat so stock is at a baresimmer. Add apricots and pineapple andpoach until tender, about 10 minutes.With a slotted spoon, remove fruit; season fruit with 1/4 teaspoon salt, 1/8 teaspoon pepper, and 1/4 teaspoon tarragon.
Raise heat to high; cook stock until reduced to 1/3 cup, 45 minutes. Reduce heattolow; whisk in mustard, 1/4 teaspoon eachsalt and tarragon, and 1/8 teaspoon pepper.
Divide the lettuce among 4 plates. Slicechicken; place on greens. Pour mustardsauce over chicken and serve with reserved apricot-and-pineapple mixture.