Beef Strogonoff

Serve with noodles or rice

1-1/2 pounds round steak
4 TBSP flour
1 tsp. salt
4 TBSP oleo
1 medium onion, sliced
1/2 cup stock or boullion cubes (sometimes increase to 1 cup if too dry)
1 tsp. prepared mustard
3/4 cup sour cream
1 large can mushrooms

Cut meat into narrow strips, 2 inches long. Dust with 3 TBSP flour and salt and pepper in a bag. Brown meat, onion and mushrooms in 2 TBSP oleo about 35 minutes. Add rest of oleo. Stir in 1 TBSP flour. Gradually stir in meat stock. Cook, stirring until thickened. Stir in mustard and sour cream. Cover and cook over very low heat for at least 1 hour. Serve over cooked noodles or rice. (Use a regular skillet, not electric, to cook more evenly.)