Add the chicken breast to a large oiled pan, season with salt and pepper and cook til browned slightly, remove from pan and set aside
In a large soup pot add curry paste, coconut milk, chicken stock, fish sauce, brown sugar, and peanut butter. Stir to combine and bring to a boil, then reduce to simmer.
Add chicken, vegetables and ginger. Stir to combine, cover and let simmer for 30 minutes.
Stir in lemon juice just before serving and server with rice on the side. Optionally garnish with cilantro.