Start by adding the oil to a large saucepan or stock pot. Place over a medium heat and add the red Thai curry paste, garlic paste, ginger paste and lemongrass paste (if using). Cook for 2 minutes, stirring frequently.

Add the chicken broth, and bring to a boil. Cook until the liquid has reduced by about half, about 5 minutes.

Next, add some unsweetened coconut milk, diced chicken, fish sauce, sweetener, and kaffir lime leaves. Stir to combine.

Cook for 15-20 minutes or until the chicken is cooked and the sauce has reduced and starting to thicken.

Add the red bell pepper and green beans, and cook for another 5 minutes.

Taste for seasoning and add more fish sauce or sweetener if necessary. Finally, add some fresh Thai basil leaves.

Serve, garnish with fresh cilantro.