Step 1

Heat 2 Tbsp. oil in a large skillet, preferably high-sided, over medium-high. Add leek, season lightly with salt, and cook, stirring occasionally, until most of it is golden brown, about 5 minutes. Transfer to a bowl; wipe out skillet.

Step 2

Pour another 2 Tbsp. oil into same skillet over medium-high. Cook brussels sprouts, in a single layer, undisturbed, until golden brown underneath, about 3 minutes. Turn over and cook until other side is browned, about 2 minutes. Transfer to bowl with leek.

Step 3

Wipe out skillet and heat remaining 2 Tbsp. oil (still over medium-high). Add curry paste, palm sugar, 2 tsp. fish sauce, and 3 whole lime leaves. Cook, stirring often, until paste darkens slightly, about 1 minute. Add pork and cook, stirring and breaking up, until in small pieces, about 2 minutes (pork doesn’t need to be fully cooked at this point). Pour coconut milk into skillet and reduce heat to medium. Simmer, stirring occasionally, until pork is cooked through and curry thickens slightly, about 5 minutes.

Step 4

Remove skillet from heat and stir in Thai basil and leek and brussels sprouts. Scatter remaining thinly sliced lime leaf over and serve with rice.