Combine first 5 ingredients. Reserve 3 tablespoons flour mixture. Pat remaining flour mixture evenly over roast.
Place roast, fat side up, on a rack in a shallow roasting pan.
Bake, uncovered, at 325° for 3 hours or until meat thermometer registers 135° or until desired degree of doneness. Remove roast from pan, reserving drippings. Let stand 10 minutes before serving.
Whisk together reserved 3 tablespoons flour mixture, 1/2 cup pan drippings (adding additional water, if necessary, to equal 1/2 cup), wine, broth, and 1/2 cup water in a saucepan over medium heat. Cook, stirring occasionally, until thick and bubbly. Serve over roast.