1. For stock, place a pot over medium high heat, and pour olive oil in it.
2. Add shrimp shells and sauté for a minute. Pour water and simmer for about 4-5 minutes. Strain and keep it aside.
3. For stew, place a pot over medium high heat for about a minute, and pour olive oil in it.
4. Add celery, carrot, and onion to it. Sauté for about 2-3 minutes.
5. Pour stock and canned tomatoes to it. Then, stir in white wine, Cajun shrimp seasoning mix, and garlic paste. Mix well, cover it with lid and simmer for 10 minutes.
6. Throw shrimp and basil paste in pot. Stir, cover, and simmer for 3 minutes.
7. Serve shrimp stew with hot rice and a glass of wine.