Chicken & Tarragon Mayonnaise Salad

This salad is based on the traditional roast tarragon chicken from French bourgeois cuisine, which is arguably my favourite dish. I have added carrots and celeriac for contrast in flavour and texture, as well as watercress for a touch of spiciness. The chicken may be cooked well in advance and cooled in the poaching liquor. To make stunning chicken sandwiches on white bread, delete the carrot and replace the celeriac with finely diced celery; they will be a hit.