To make stuffing: Melt butter in a large skillet. Saute onion and celery until transparent. Add bread cubes and toss lightly. Set aside.
Cut 6 pieces of string into 12 to 15-inch lengths and place strings, stretched out, on counter. Lay round steak over string lengthwise. Mound the stuffing lengthwise on steak. Roll steak up and around stuffing and secure by knotting strings tightly. Cut off excess after knotting.
Using the same large skillet; heat olive oil to hot but not smoking. Add steak roll carefully and braise quickly on all sides. Add small amount of water and cover pan. Reduce heat to medium and continue cooking for about 1 to 1 112 hours until desired doneness. Do NOT allow pan to get dry. Add additional water in small amounts at a time as needed.
When ready to serve, remove steak roll from skillet and place on cutting board. Cover with· foil and let rest about 15 minutes. Meanwhile prepare the gravy.
To make gravy, place skillet over medium high heat and loosen all the bits of drippings in the pan. Add water or beef broth to make about 2 cups of liquid. Bring rapidly to a full boil. Salt to taste. In a small bowl, mix 112 cup cold water and 5 tablespoons flour to make a smooth paste. While liquid in skillet is boiling, stir in paste, whisking rapidly so it does not become lumpy.
To serve, remove cords or strings and slice across roll to make even slices. Place on serving plate and drizzle gravy over slices. Makes 6 servings. Enjoy!