Prep the chicken: Use leftover roasted chicken, poached chicken, or a rotisserie chicken.
Chop or shred into bite-size pieces. Aim for a mix of textures, not too fine.
Dice the vegetables: Finely chop the celery and onion or scallions. Keep pieces small so they blend evenly without overpowering each bite.
Make the dressing: In a large bowl, stir together mayonnaise, Dijon, lemon juice, a pinch of salt, and pepper.
Taste and adjust the acidity or creaminess to your liking.
Combine: Add the chicken, celery, and onion to the bowl. Fold gently until everything is evenly coated. If using herbs or add-ins (like nuts or grapes), mix them in now.
Adjust seasoning: Taste and add more salt, pepper, or lemon.
If it’s too thick, loosen with a teaspoon of water or a splash of lemon juice.
Chill: Cover and refrigerate for at least 30 minutes. Chilling lets flavors meld and firms up the texture.
Serve: Spoon onto toasted bread, pile into lettuce cups, wrap in a tortilla, or serve with crackers and cucumber slices.