Ingredients

1/4 cup low-fat plain yogurt

1 tablespoon fresh lemon juice

1/2 teaspoon coarse salt

1/4 teaspoon ground pepper

1 (about 2 cups) apple, cored and cut into 1/2-inch pieces

1 (about 1/2 cup) celery, thinly sliced crosswise

1/2 cup halved red seedless grapes

4 Boston lettuce leaves

1/2 cup chopped toasted walnuts

Preparation

In a medium bowl, whisk together yogurt and lemon juice; season with coarse salt and ground pepper.

Add apple, celery, red seedless grapes, and toasted walnuts; toss to coat with dressing. Cover; refrigerate until ready to serve, up to overnight.

Divide salad in half; serve each portion on 2 Boston lettuce leaves.