1. In a bowl, whisk together 3 tablespoons mayonnaise, 2 tablespoons white wine vinegar, 1 tablespoon Dijon mustard, 1 tablespoon fresh thyme leaves (or 2 teaspoons dried thyme), and 1/4 teaspoon fresh-ground pepper.
2. Add 3 cups shredded cold cooked chicken, 3/4 cup chopped watercress or Italian parsley, and 2 tablespoons chopped shallots. Stir in salt to taste.
3. Serve with toasted baguette slices.