Julie Stanton's Paupiettes de Bouef aux Saucisson - Stuffed Flank Steak with Sausage

1 pound bulk sausage, such as Bob Evans2 tablespoons onion, finely chopped2 large flank steaks (about 1 1/2 pounds each)Garlic powder to taste 1/4 teaspoon celery salt, plus more to taste 1/4 cup flour 1/4 teaspoon celery saltOlive oil1-2 cups red Burgundy wine1-2 cups canned beef stock2 tablespoons butter1 pound mushrooms, sliced2 tablespoons Wondra1 tablespoon water4 tablespoons Italian parsley, choppedHeat oven to 350 degrees.Combine sausage and onions in bowl.Sprinkle flank steak to taste with garlic powder and celery salt; spread sausage mixture over steaks and roll up, jelly-roll style, folding in ends if they hang out. Tie rolls in several places with kitchen twine.In a small bowl, combine flour and 1/4 teaspoon celery salt; dust meat with flour mixture.Heat thin layer of olive oil in oven-proof skillet or Dutch oven and brown meat on all sides. Pour in enough wine and beef stock to cover meat half way. Cover dish and braise in oven 2 hours or until tender, basting meat several times.After 1 hour, turn meat over; add more wine and beef broth if necessary.Remove meat to hot platter, cut off strings and cover with foil to keep warm. Skim fat off cooking liquid.In a deep skillet melt the butter and sauté the mushrooms until tender. Remove from heat. Mix 2 tablespoons Wondra with the water and stir well. Add to mushrooms, return to heat and cook several minutes, stirring constantly. Add all cooking liquid from beef and simmer until thickened as desired. Add more wine if desired.To serve: Slice meat and place on platter or individual plates. Spoon sauce over and pass remaining sauce. Garnish with parsley.Serves eight.Cook's note: If you don't have oven-proof skillet, brown the meat in a skillet and transfer to a 9-by-13-inch baking dish. Proceed as directed. All-purpose flour can be substituted for the Wondra.Nutrition values per serving: 491 calories, 27 g fat (11 g saturated), 9 g carbohydrates, 1 g fiber, 44 g protein, 120 mg cholesterol, 724 mg sodium.