Heat the vegetable oil in a large skillet or wok over medium heat.

Add the Panang curry paste and stir-fry for about 2 minutes until it becomes fragrant and darker in color.

Pour in about 1/2 cup of the coconut milk and stir continuously until the oil starts to separate from the paste.

Add the sliced chicken thighs to the pan and cook for 3-4 minutes, stirring to coat the meat in the curry base.

Pour in the remaining coconut milk and stir in the peanut butter, fish sauce, and sugar.

Reduce the heat to low and simmer gently for 10-15 minutes, allowing the sauce to thicken and the chicken to cook through completely.

Add the sliced red bell pepper and cook for an additional 2-3 minutes until tender-crisp.

Turn off the heat and stir in the sliced kaffir lime leaves.

Serve hot over steamed jasmine rice, garnished with fresh basil leaves.