(from Bon Appetit, November 1995)
Nonstick vegetable spray
6 medium onions (about 2 ½ pounds), peeled each cut vertically through root end into 12 to 14 wedges
6 tablespoons (3/4 stick) butter
2 cups canned low-salt chicken broth
3 tablespoons sugar
2 tablespoons red wine vinegar
3 pounds slender green beans, ends trimmed
Preheat oven to 450°F. Spray two heavy large baking sheets with vegetable oil spray. Arrange onions in single layer on prepared sheets.
Dot onions with 4 tablespoons butter, dividing equally. Season with salt and pepper. Bake until onions are dark brown on the bottom, about 35 minutes.
Meanwhile, boil broth in heavy large skillet over high heat until reduced to ½ cup, about 6 minutes. Add sugar and vinegar and whisk until sugar dissolves and mixture comes to a boil.
Add onions to sauce; reduce heat to medium-low. Simmer until liquid is slightly reduced, about 5 minutes. Season with salt and pepper. (Can be prepared 1 day ahead. Cover and refrigerate. Rewarm over low heat before continuing.)
Cook green beans in large pot of boiling salted water until crisp-tender, about 5 minutes. Drain well. Return beans to same pot. Add remaining 2 tablespoons butter and toss to coat. Mound beans in large shallow bowl. Top with onion mixture and serve.