Ingredients

• 2 pounds red or brown all-purpose potatoes
• 2 tablespoons white wine vinegar
• Salt and freshly ground pepper to taste
• 2 cups Gruyere or Swiss cheese, cut into ¼" cubes
• 2 cups diced celery
• Green-leaf lettuce leaves
• ½ cup coarsely chopped walnuts, lightly toasted

  Dressing

• 1 cup mayonnaise
• 1 tablespoon Dijon mustard
• 1 tablespoon Worcestershire sauce

Cover the potatoes with cold water, bring to a boil and boil gently for 15 to 20 minutes, test for doneness. Drain.

When cool enough to handle, peel and cut into ¼" cubes. Place the cubes in a large bowl. Sprinkle with vinegar, salt and pepper and let cool. Add the cheese and celery to the potatoes. Toss gently.

To make the dressing, stir together the mayonnaise, mustard, and Worcestershire sauce in a small bowl.
Add the dressing to the potato mixture and stir gently but thoroughly.

Line a bowl with the lettuce leaves. Pile the potato mixture on the greens and sprinkle with the walnuts.
Cover and refrigerate for up to 2 days. Serve chilled.