1-1/2 pounds boneless, skinless chicken breasts
1/2 cup orange juice
3 large navel oranges
1 fennel bulb, trimmed and coarsely diced
8 cups mixed lettuce such as Boston or Bibb, washed and torn into bite-size pieces
1 small red onion, thinly sliced
1/4 cup raspberries

Tangy Raspberry-Orange-Mustard Dressing:
3 tablespoons olive oil
3 tablespoons grainy mustard
3 tablespoons honey
2 tablespoons raspberry vinegar
1 large navel orange, zest grated and juice squeezed
Salt and freshly ground black pepper, to taste

Set 4 dinner plates in the refrigerator.

In a medium bowl, whisk together all ingredients for the dressing. Spoon 2 tablespoons of dressing into a large skillet and set the rest aside.

Over medium-low heat, add chicken and orange juice to skillet. Bring to a simmer, reduce heat to low and cover the pan. Cook chicken for 6 minutes, then turn it over and cook for another 6 minutes. Shut off heat, remove lid, and let cool in the pan for 15 minutes.

Meanwhile, cut off tops and bottoms of remaining 3 oranges with a sharp paring knife; peel the oranges, removing all the white pith, and slice into rounds.

In a large bowl, toss the fennel and lettuce with all but 2 tablespoons of the reserved dressing. Divide the lettuce mixture among the 4 chilled dinner plates. Slice the chicken into thin strips. Arrange the chicken, orange sections and onion slices on top of lettuce. Drizzle with remaining dressing, sprinkle with raspberries and serve.