Clean the seafood: rinse the large shrimp and peel if needed, soak mussels or clams in salted water for 30 minutes, cut squid into rings.

In a large pot, bring water to a boil and cook the Korean fresh noodles for 3-5 minutes until al dente. Drain and rinse with cold water.

Heat 2 tablespoons of neutral oil in a wok over medium heat, stir-fry yellow onion, carrot, green onion, and minced garlic for 2-3 minutes.

Add napa cabbage to the mixture and cook for another 2 minutes.

Sprinkle gochugaru into the stir-fried veggies, stir for 30 seconds. Pour in 4 cups of water, add soup stock tablet, salt, and optional MSG. Bring to boil for 5 minutes.

Add shrimp, mussels, and squid into the boiling broth and simmer for 3-5 minutes until shrimp are cooked and mussels have opened.

Warm the cooked noodles in boiling water for a minute, divide into bowls, and ladle the soup with seafood and vegetables over them.