Mix together the red curry paste with the ground toasted cumin seeds, coriander seeds, and ground roasted peanuts to make the curry paste
Add fish sauce and oil to the sliced pork tenderloin and mix to combine, then set aside to lightly marinate
In a wok over medium-high heat, reduce about ¾ cup of the coconut milk until it's thick and creamy
Lower the heat to medium-low and stir in the Panang curry paste
Cook for a few minutes, stirring constantly, until the coconut oil starts to separate from the paste
Add the brown sugar and torn makrut lime leaves if using, and cook for another minute until the sugar has dissolved
Add the pork to the wok and toss through the curry paste, separating the slices as much as possible
Once the pork is around halfway cooked, pour in the rest of the coconut milk
Stir through for another minute or so until the pork is just cooked, then turn off the heat
Taste and adjust with more fish sauce if needed
Serve the curry in a bowl, drizzling over a little extra coconut milk
Garnish with fresh Thai basil and sliced red chilli, and enjoy with steamed jasmine rice
