5	pounds (2,400 g) skinless, boneless chicken breasts

3/4	cup (150 g) nonfat sour cream

3/4	cup (150 g) nonfat mayonnaise

2	tablespoons (30 ml) white wine vinegar

4	celery ribs, strings removed, and cut into small dice

1/2	cup (75 g) walnuts

1/4	cup (12 g) chopped fresh tarragon

freshly grated pepper

extra tarragon for garnish

1. Poach the chicken breasts in simmering broth until cooked through, about 15 minutes. Drain, cool, and cut into bite-sized pieces.
2. In a small bowl, combine the sour cream, mayonnaise and vinegar.
3. Combine the chicken and dressing. (Can be made ahead and refrigerated to this point 1 day in advance.)
4. Before serving, add the celery, walnuts, tarragon and pepper to taste. Place mixture in a large serving bowl. Garnish with tarragon.