- 1 large red onion, halved lengthwise, thinly sliced crosswise
- 1/4 cup plus 6 tablespoons balsamic vinegar
- 6 large beets (about 2 1/2 pounds)
- 1 tablespoon plus 1/2 cup extra-virgin olive oil
- 1 1/2 pounds slender green beans, trimmed, cut in half crosswise
- 1 tablespoon minced fresh thyme
- 1 large head of radicchio
Place onion, 1/4 cup vinegar, and bay leaf in large jar or medium bowl. Add just enough water to cover. Season generously with salt and pepper. Cover and chill overnight. DO AHEAD Can be prepared 3 days ahead.
Preheat oven to 350°F. Place large piece of foil on baking sheet. Place beets in center of foil. Drizzle beets with 1 tablespoon oil and 2 tablespoons water. Top with another piece of foil; crimp edges to seal tightly. Roast beets until tender when pierced with fork, about 1 hour 15 minutes. Cool completely.
Cook beans in large pot of boiling salted water until crisp-tender, about 6 minutes. Rinse under cold water to cool. Drain and pat dry.
Whisk remaining 6 tablespoons balsamic vinegar, 1/2 cup oil, shallots, and thyme in small bowl to blend. Season dressing with salt and pepper. DO AHEAD Beets, beans, and dressing can be made 1 day ahead. Cover separately and refrigerate.
Peel and cut beets into 1/4-inch-thick slices. Arrange large radicchio leaves over very large platter to cover (reserve small leaves for another use). Drain red onions; scatter over radicchio. Arrange beans over onions. Arrange beet slices decoratively over beans. Pour dressing over salad and serve.