1 cup walnut halves

1/2 cup mayonnaise

1/4 cup plain yogurt

1 teaspoon prepared mustard

Pinch of dry mustard

Juice of 1/2 lemon

4 to 6 tart apples, peeled, cored, and diced (2 cups)

1 to 2 cups finely diced inner ribs celery

(white part only), leaves reserved

Salt and freshly ground black pepper

2 bunches tender greens, such as arugula, baby kale,

or pepper cress, washed and dried

2 tablespoons olive oil

1 tablespoon fresh lemon juice

Preheat the oven to 325F.

Spread the walnuts on a baking sheet and toast in the oven

for 4 to 5 minutes, until aromatic and lightly toasted.

Let cool.

Combine the mayonnaise, yogurt, both mustards, and the lemon juice

in a large bowl. Fold in the apples and diced celery and

season with salt and pepper.

Put the salad greens in a large bowl. Add the olive oil and lemon juice,

season with salt and pepper, and toss well. Divide the greens among four

plates. Spoon the apple mixture onto the greens and sprinkle with the

toasted walnuts and reserved celery leaves.