Heat a medium sized frying pan on a medium heat and add the curry paste, cooking for a couple of minutes until fragrant. Add the chicken and saute for 4-5 minutes. You may need to add a couple of TBSP of water to help the curry paste coat the chicken.
Pour in the coconut milk and water and reduce the heat to low. Simmer for 20 minutes stirring occasionally until the chicken is cooked and the sauce is starting to thicken up. You may need to add more water depending on how thick you want the sauce to be.
Stir in the fish sauce & brown sugar and serve with rice.
* You can buy yellow curry paste or make it using my recipe here** You can use either canned coconut milk or coconut cream here. If using coconut cream, the curry will be creamier and thicker so you may need to add slightly more water.