Add Chicken (2 cup), Celery (1/4 cup), Celery Leaves (1 tablespoon), Whole Grain Mustard (1 tablespoon), Dried Tarragon (1 teaspoon), Kosher Salt (to taste), Ground Black Pepper (to taste) and squeeze of Lemon Juice (to taste) to a medium-size bowl.
Add Mayonnaise (1/3 cup). Stir gently until combined, adjusting creaminess with additional mayonnaise and seasoning to taste with salt and pepper.
Cover and refrigerate for at least 20 minutes and up to several hours to allow flavors to meld. The tarragon flavour will become more pronounced the longer the chicken salad sits.
Serve on buns with toppings of choice, on top of some crackers, or in a lettuce wraps for a low-carb lunch option!