Best Chicken Salad
About 4 pounds of chicken breasts
2 scallions, cut into thirds
¼ teaspoon black peppercorns
1 lemon, halved
⅔ cup mayonnaise
¼ cup sour cream, more to taste
½ teaspoon Dijon mustard or 1 teaspoon brine from a jar of pickles, optional
2 or 3 pale green celery ribs, cut into medium (¼-inch) dice
½ cup minced onion
½ cup walnut halves , broken into bite-size pieces
3 tablespoons chopped fresh parsley or chives, plus extra for garnish
Salt and ground black pepper, to taste
Choose a heavy pot or Dutch oven with a tight fitting lid. It should be large enough to hold the chicken snugly, but not much bigger. Fill pot about ⅔ full with cold water, but don’t put the chicken in yet. Boil some extra water in a teakettle.
Add scallions and peppercorns to water, cover and bring to a rolling boil. Turn off heat and slip chicken pieces into the hot water. If needed, add boiling water from the kettle to cover chicken with water by 2 inches. Replace the lid and let chicken rest in the hot water for about 2 hours. Do not turn the flame back on: The pot will retain enough heat to cook chicken thoroughly and safely. (To test, cut into 1 piece of chicken and check the meat. If it is still pink, return the pot to low heat, bring the water to a simmer and simmer 10 minutes more.)
Lift chicken out of the pot. Pat the meat dry with paper towels, then cut or shred into small bite-size pieces and transfer to a bowl.
In a bowl, whisk together juice of ½ lemon, mayonnaise and sour cream. If using, whisk in mustard or brine. Taste and adjust the seasonings and thickness to your liking. Pour over chicken, scraping the bowl clean with a rubber spatula.
Add celery, onion, nuts, herbs and salt and pepper. Toss gently but thoroughly. Refrigerate, covered, at least 4 hours. Taste and add salt and pepper as needed. Sprinkle with herbs before serving.