Turkey Velouté

1˝ TBS unsalted butter
1˝ TBS flour
1 cup turkey stock, warmed
1 TBS chopped rosemary or sage
1 TBS white wine vinegar
salt and white pepper to taste

Melt butter in a saucepan over medium heat. Stir in the flour and cook for 3 minutes for a blond roux, stirring constantly. Slowly pour in the warmed turkey stock, whisking constantly. Add the herb of choice and bring sauce to a simmer. Skim the sauce if necessary. Reduce the sauce until it coats the back of a spoon. Season with salt and white pepper to taste.