Cube Steak Stroganoff

1 medium white onion, chopped
4 T butter
1/4 pound sliced mushrooms
1 1/2 pounds cube steak, cut in 1-inch strips
1 C beef broth
2 T lemon juice
1 C sour cream

Saute the onion in one tablespoon butter until golden. Remove from pan, add another tablespoon butter, and cook the mushrooms, about five minutes. Remove from pan. Flour the steak strips lightly and brown them in the remaining two tablespoons butter. Return onions and mushrooms back into pan; add beef broth and lemon juice. Simmer for 15 minutes, add the sour cream and heat gently. Makes about 4 servings.  Serve with noodles or mashed potatoes or rice.