1 pound green beans, stem ends snipped off
1 tablespoons butter
1 medium onion, sliced as thinly as possible
1 cup chicken or vegetable stock
2 teaspoons sugar
2 teaspoons red wine vinegar
Salt and pepper to taste

Cook beans in boiling salted water until crisp-tender, 2-4 minutes.  Drain;  immerse in ice water.  Drain again and let stand to dry.  Melt butter in skillet over medium flame.  Stir in onions and cook them slowly until very wilted and deepened in color, about 15 minutes.  Boil stock in a saucepan until reduced to 1/4 cup;  stir in sugar and vinegar.  Stir in onions.  Simmer until slightly reduced.  Combine onions and green beans;  heat through. Season with salt and pepper.

– From Asparagus to Zucchini:  a guide to cooking farm-fresh seasonal produce