1. Preheat the oven to 350°F.
2. Season the turkey breast on all sides with 2 teaspoons of the salt and 1/2 teaspoon of the pepper. Place the turkey in a small roasting pan or on a baking sheet, and roast for 30 minutes. Then brush the turkey with 2 tablespoons of the olive oil and continue to roast for another 30 minutes, or until the thickest section registers an internal temperature of 165°F on an instant-read thermometer. Remove the pan from the oven and loosely tent it with aluminum foil. Let the turkey rest for at least 15 to 20 minutes. Once the turkey has rested, remove the breast bone and cut the turkey into thin slices.
Set aside on a platter.
3. To make the Waldorf dressing, in a medium bowl, combine the chopped pecans with the 1/2 cup yogurt, the 1/4 cup mayonnaise, the parsley, and the vinegar. Season with 1/2 teaspoon salt and 1/4 teaspoon pepper.
4. Halve and core the apple; then cut it into thin slices on a mandolin. In a medium bowl, toss the apple slices with the lemon juice, celery, and cherries. Then add the dressing and toss.
5. In a small bowl, combine the remaining 2 tablespoons olive oil, 2 tablespoons yogurt, 2 tablespoons mayonnaise, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Mix well.
6. To assemble: Place 4 slices of the toast on a clean work surface. Spread 1 tablespoon of the yogurt-mayonnaise mixture on each slice of toast. Top each one with lettuce leaves, several slices of turkey, 3/4 cup of the apple salad, and 1/4 cup of the sprouts. Top with the remaining slices of toast. Cut each sandwich in half, and serve immediately.
Yield: 4 sandwiches
Note: Any leftover roast turkey will keep, well wrapped and refrigerated, for up to 3 days.