2 teaspoons freshly grated orange zest
1/4 cup orange juice
2 tablespoons balsamic vinegar
1 tablespoon minced shallot
1 teaspoon Dijon mustard
1/2 teaspoon salt
1/2 teaspoon freshly ground pepper
1 1/2 tablespoons extra-virgin olive oil
3 small navel oranges
2 bunches arugula or watercress, stemmed, washed and dried (about 4 cups)
1 small head romaine lettuce, washed, dried and torn (about 4 cups)
1 small red onion, thinly sliced
Whisk together orange zest and juice, balsamic vinegar, shallot, mustard, salt and pepper in a small bowl. Whisk in the oil until well blended.
Remove the rind and white pith from the oranges with a very sharp knife and discard. Slice oranges thinly, or remove the individual segments by slicing between the membranes. Halve the orange slices if they are large.
Toss the arugula and romaine together in a shallow salad bowl. Separate the onion slices into rings. Scatter the onions and oranges over the greens. Drizzle the vinaigrette over the salad and toss.