Toss the apple, celery and shallots in a bowl with the lemon juice.
Peel the beet, then slice into matchsticks and add to the bowl. Toss in the sugar, walnuts and olive oil. Season with the salt and pepper. Let stand 10 minutes if time allows, then serve on a bed of the sliced endive.
Courtesy of Food Network Magazine, Photograph by Con Poulos