1 1/2 pounds green beans, trimmed and cut into 1 1/2-inch pieces
1 Maui or Vidalia onion, halved and sliced thin
6 tablespoons extra-virgin olive oil
2 tablespoons balsamic vinegar
1 1/2 teaspoons packed brown sugar
Salt and freshly ground black pepper to taste
On a steamer rack set over boiling water steam green beans, covered, until crisp-tender, about 4 minutes.
In a large serving bowl whisk together the oil, vinegar, brown sugar, salt and pepper. Add the warm beans and onion and toss to coat well.
Serves 6.