Combine the garlic, ginger, jalapeno, salt and turmeric in the container of a food processor or blender. Process to a smooth paste. Set aside.

Heat oil in a skillet over medium heat. Add onion, and cook until translucent, stirring frequently. Mix in the spice paste, and cook for a few minutes to release the oils.

Add shrimp, and cook for a few minutes until pink, then add the tomatoes and coconut milk. Cover, and simmer for about 5 minutes, then remove the lid and simmer an additional 5 minutes to thicken the sauce. Stir in the fresh basil during the last minute of cooking.