Cook the pasta: Bring a pot of salted water to a boil. Cook the spaghetti until just al dente according to package directions. Reserve about ½ cup (120 ml) pasta water before draining.
Start the sauce toward the end: When the pasta is almost done, heat the olive oil and perilla oil in a large pan over low heat. Add the garlic and dried chili. Let it gently infuse until fragrant. Keep the heat low so the garlic softens without browning.
Warm the myeongran: Add the myeongran and stir briefly. Cook for about 1–2 minutes, just until it turns slightly lighter in color. Avoid overcooking so it stays soft and delicate.
Toss with pasta: Add the drained spaghetti to the pan along with a splash of reserved pasta water. Toss gently to coat the noodles evenly. Add more pasta water as needed to loosen the sauce.
Finish and serve: Transfer to serving plates. Drizzle with a little extra olive oil if desired, then top with green onion, perilla leaves, ground perilla seeds, and parmesan. Serve immediately.