Preheat oven to 350 degrees. Cut the steak into smaller pieces for individual servings. Coat with flour and sprinkle with salt and pepper. In a hot skillet, brown steak in 1 Tbs of oil. Add more oil if pan dries up and meat starts to stick.
After browning steak but not cooking all the way through, remove meat from pan and place into a deep casserole dish. Atir 1/4 cup water into hot pan. It should sizzle and dissolve browned bits on the pan. Pour water and meat juices over steaks.
Pour half of tomato sauce over steaks, then cover with chopped onion, green pepper, mushroom and 1 Tbs of leftover flour. Pour remaining tomato sauce over steaks.
Bake in covered casserole dish in a 350 degree oven for 1 to 1 1/2 hours, until steak is tender enough to be cut with a fork and sauce is thick. Makes many servings, and it tastes great reheated the next day. Enjoy!