Heat oil in a large pot over medium heat. Add onion and cook for 3-4 minutes until softened.
Stir in the red curry paste and ginger and cook for 30 seconds.
Add the chicken broth, coconut milk, chicken breasts, lime juice, and brown sugar. Bring to a boil, then reduce to a simmer and cook for 15 minutes until the chicken is fully cooked.
Remove the chicken to a bowl and shred with two forks.
Return the chicken to the pot. Add the cilantro and season with salt and pepper to taste. Serve with freshly cooked noodles or rice. Enjoy!