Heat oil in a large skillet over medium-high heat. Add the curry paste and cook for 2 minutes, stirring constantly, until it dries out and becomes very aromatic.

Add chicken broth and stir to dissolve the paste. Simmer for 3 minutes until the liquid reduces by half.

Pour in coconut milk and add kaffir lime leaves, sugar, and fish sauce. Stir in the chicken and simmer for 8 to 10 minutes until the sauce reduces and chicken is cooked through.

Add pumpkin cubes and green beans. Cook for 3 minutes until vegetables are tender. Taste and adjust seasoning with additional fish sauce or sugar as needed.

Remove from heat and stir in Thai basil. Serve over steamed jasmine rice, garnished with fresh chilli slices and cilantro.