Peel the shrimp reserving the shells for stock
SHRIMP STOCK-Place shrimp shells in a pot with 4 cups of water and simmer for 30 minutes
Season the shrimp with salt, pepper and cayenne
Strain the shrimp stock- you should have about 2-1/2 cups of stock
In a large pot melt the butter over medium heat
Saute the shrimp in the butter for 2 minutes per side. Remove shrimp from pan and reserve in the refrigerator
Add the flour to the remaining butter in the pan and cook on medium low heat until the roux is golden brown, about the color of peanut butter.
Add the diced red bell pepper, onion, celery and scallions and cook for 3-4 minutes
Add the chopped garlic and cook for 30 seconds
Pour in the shrimp stock and diced tomatoes in sauce, stir and let simmer for 20 minutes. The mixture will start to thicken
Add shrimp and simmer for 3 minutes until heated through