In a large mixing bowl, combine the chopped onion, turmeric, ginger, lemongrass, lime zest, and curry powder. Mix well to coat the chicken drumsticks.
Pour in the coconut milk, lime juice, coconut aminos, and fish sauce. Stir until the marinade is well combined.
Add the chicken drumsticks to the bowl, ensuring each piece is coated. Cover and marinate in the fridge for at least 1 hour, or overnight for maximum flavor.
Preheat the oven to 375°F (190°C). Transfer the marinated chicken drumsticks to a baking dish and pour any remaining marinade over the top.
Roast the chicken in the oven for 35-40 minutes until fully cooked, basting occasionally with the juices from the dish.
For extra crispiness, broil the drumsticks on high for an additional 3-5 minutes at the end.
Garnish with additional lime zest or cilantro before serving.