In a large pot, heat vegetable oil over medium heat. Add chopped onion and cook until translucent, about 5 minutes.
Add minced garlic and grated ginger to the pot and cook for another 2 minutes.
Stir in gochujang and cook for 1 minute to release its flavors.
Pour in chicken or seafood broth, water, soy sauce, fish sauce, mirin, and sesame oil. Bring the mixture to a simmer and let it cook for 10 minutes to allow the flavors to meld together.
Add the seafood mix to the pot and cook for 5 minutes, or until the seafood is cooked through.
While the soup is simmering, cook the ramen noodles according to the package instructions. Drain and set aside.
Divide the cooked ramen noodles among four bowls. Ladle the spicy seafood broth over the noodles.
Garnish each bowl with sliced green onions, halved soft-boiled eggs, and cilantro leaves.
Serve hot and enjoy!