Season the chicken thighs with salt and pepper.
Coat the chicken thighs with cornstarch.
Sauté the onion, garlic, ginger, and cilantro stems in a pan.
Add the tomato paste, pepper, and pepper flakes (if using).
Pour in the water and coconut milk, then add the seasoning granules.
Add the chicken thighs and simmer until the chicken is cooked through.
Garnish with cilantro leaves.
