Prepare your chicken by poaching it in simmering water for about 15-20 minutes until cooked, or use rotisserie chicken.

Chop 1 cup of celery and a handful of flat-leaf parsley, set aside.

In a large mixing bowl, combine ½ cup of mayonnaise, 1 tablespoon of Dijon mustard, 1 teaspoon of salt, and black pepper. Mix in lemon juice and zest.

Add the diced chicken, chopped celery, pecans, and parsley to the bowl. Gently fold together.

Serve the chicken salad on slices of bread topped with arugula, then slice the sandwiches in half.