Cut beef into narrow 2-inch long strips about 1/2-inch thick. Sprinkle meat with salt. Melt 1 tablespoon of butter and 1 tablespoon olive oil in a frying pan over medium heat; brown meat strips. Remove meat and set aside. In the same pan sauté onion (celery). Add meat and onions (celery). In seperate sauce pan melt remaining butter and flour and slowly adding in beef broth until sauce thickens stirring frequently until smooth. Add in meat and veggies. Cover and cook on low for 10 minutes and heat through but do not boil. Serve over egg noodles, rice, or mashed potatoes.