- In a bowl, combine the mayonnaise, Dijon mustard, horseradish, vinegar, white wine, capers and green onion. Season with salt and pepper.
- Add the celery root and blend well. Let stand for 1 hour before serving.
- Place the salad on the Boston lettuce leaves. Garnish with thin strips of red pepper.
You can easily and quickly grate the celery root in a food processor. However, if you must do by hand, grate it over a bowl containing a little lemon water to prevent the celery root from oxidizing.