Begin by salt and peppering roast, then brown roast in butter in a frying pan, once browned on all sides place in roaster with cut up onion. Put 1/4 cup of water in in frying pan to deglaze pan. Put deglaze in roaster and place in 350 degree oven for 1/2 to 2 hours. Sauce: 1 cup pomegranate juice, 1/2 cup butter. Put pomegranate juice in pot on stove and bring to a high simmer. Cut butter into 4 pieces and melt 1 piece at a time into juice until juice is velvety and smooth.