This is ridiculously easy if you keep all the ingredients around.
4 to 6 chicken thighs, roasted and diced
If there’s skin or bone, remove that and use for soup.
One granny smith apple, diced finely
4 ribs of celery, diced finely
¾ cup sweet onion, diced finely
½ t salt
¼ t fresh ground black pepper
1 T sugar
1 T whole celery seed
Pound all this in a pestle until the celery seeds are bruised and aromatic.
Put the spices in a small jar with a secure lid containing:
¾ to 1 cup mayonnaise
¼ cup cider vinegar
Cover the jar securely and shake until the sugar and salt are dissolved.
Tump everything into a good-sized bowl and stir until all ingredients are coated.
Cover and chill until ready to eat. Can be eaten immediately if desired.