Red Wine Mushroom Sauce

INGREDIENTS:
1 med onion
4 garlic cloves
1 sprig rosemary
1-lb. mushrooms, sliced
1 cup red wine
2 cups lamb or veal stock
1 Tbs. flour
2 oz. butter
Salt and Pepper

Sauté onions until golden brown, add garlic and mushrooms,
and then sauté two more minutes. Add wine, reduce in half,
whisk in flour, sauté one minute while whisking. Add stock
and reduce by 25%. Whisk in butter off the heat before
serving over lamb, beef or even chicken.