In a skillet, melt half the butter & sauté onion until soft; add the barley & mix until coated with butter. Add the wine, stir & allow to evaporate. Heat the broth & add a ladle to onion/barley mixture & leave until most of the broth is absorbed. Uncover, add some more broth; do not let the barley dry out. Cook barley until it is soft, over a medium heat. It should take about 20 minutes. Season with salt & pepper to taste.