New Orleans Style Shrimp Creole

I have been in a cajun mood recently, but all of the authentic recipes that I was finding had clam sauce or shrimp shell stock... not too appealing. I ran into this recipe on Tasty Kitchen this weekend. Granted, I don't know what authentic shrimp creole tastes like, but this is really good and really easy.

New Orleans Style Shrimp Creole
Adapted by Tasty Kitchen member Frank

Ingredients
1 lb medium shrimp, peeled and deveined
1 Tbsp butter
1 Tbsp olive oil
3 Tbsp flour
1 cup yellow onion, chopped
1 cup celery, chopped
1 cup green bell pepper, chopped
2 cloves garlic, chopped (I used five)
8 oz can tomato sauce
14 oz can chicken broth
1 tsp lemon juice
2 whole bay leaves
1/8 tsp black pepper
1/8 tsp white pepper
1/8 tsp cayenne pepper (I used 1/4 tsp - warning - spicy!)
salt, to taste
2 cups boiled rice (I used two success boil-in-bags)

Directions
In a black cast iron pot, melt butter. (I don't have a black cast iron pot, so I used a 12" frying pan with lid.) Add the oil. Over medium heat, saute the onion, celery, green bell pepper, and garlic for about 5 minutes. Add the flour and blend well. Add the tomato sauce, chicken broth, lemon juice, bay leaves, black pepper, white pepper, cayenne pepper, and salt. Bring to a low boil then reduce the heat and simmer for 30 minutes. Add shrimp, cover, and simmer for 20 minutes longer. Remove the pot from the heat and allow to stand at room temperature for about 10 minutes before serving. Serve over cooked rice.