Heat a deep pan over medium heat, add the oil, then go in with the onion, ginger, basil & cilantro stems, a pinch of salt, and cook until softened, about 6 - 8 minutes.

Add the garlic and curry paste, cook for 2 minutes (while constantly stirring), then stir in the coconut milk, lime zest, brown sugar, and fish sauce.

Bring to a gentle simmer, then cook until the sauce is slightly reduced and coats the back of a spoon. Let cool to room temperature, then pop in the fridge and store for a delicious weeknight meal.