Heat oil in a skillet. Sauté lemongrass over medium-high heat for 2 minutes, stirring frequently.
Add pork to skillet and cook for 3 minutes, breaking it up into bits with a spoon. Strain pork and return to pan. Add sugar, fish sauce, and Momofuku Black Truffle Chili Crunch. Stir to combine. Wait 2 minutes, then stir again. Increase heat to high. Wait 2 minutes, then stir again. Repeat.
Reduce heat to low and keep warm. Prepare Momofuku Sweet & Spicy Noodles according to package instructions.
To serve, place noodles in a bowl, toss with included sauce packets, and top with caramelized pork. Garnish with green onion and bird’s eye chili pepper.
