Place shrimp in lg bowl, sprinkle w/ salt, pepper and lemongrass. Heat 1/4 cup oil in lg skillet over medium heat. Add shrimp and saute until pink.
Remove shrimp from skillet. Add remaining oil to skillet. Add onion, garlic, celery and red bell peppers. Cook, stirring for 2 mina. Add tomatoes. Reduce heat to med-low. Simmer for 5 mins. Add bayleaf, allspice and red pepper flakes. Simmer, stirring for 10 mins.
Place shrimp back in skillet and basil. Cook 2 mins. Remove bayleaf. Serve over rice.