Heat oil in a large skillet or dutch oven over medium-high heat. Add onion, scallions, green and red peppers, scotch bonnet, or other chili pepper and 1 tsp salt. Cook until very soft, about 15 minutes.
Add garlic and curry powder; cook 1 minute more.
Add coconut milk and thyme along with remaining salt. Bring to a boil then reduce heat to low and simmer for 2 minutes.
Add shrimp and cook 3-5 minutes until shrimp are just opaque (smaller shrimp take less time to cook, larger ones take longer).
Video
Notes
Scotch bonnet peppers are extremely spicy and not always easy to find. The closest pepper to substitute is 1 habanero pepper, but you can use 2 Thai red chilies or 2 green chilies.Keep in mind the size of your shrimp when you're cooking them; a key goal with this recipe is not to overcook your shrimp. Keep an eye on your garlic so that you don't burn it and turn the sauce bitter.