In a medium bowl, combine ¼ cup soy sauce and 2 tablespoons sesame oil. Add 1 pound of sliced flank steak or sirloin, ensuring the beef is fully coated. Cover and let marinate for at least 30 minutes.

Preheat your grill or skillet over medium-high heat. Grill marinated beef strips for 2-3 minutes on each side until browned. Set aside to rest.

Bring a large pot of water to a boil and cook ramen noodles according to package instructions (4-5 minutes). Drain and rinse with cold water.

In a pot, combine 2 tablespoons go chu jang and 1 cup of heavy cream over medium heat. Stir for about 3-4 minutes until smooth.

Stir in 1 cup of sliced mushrooms and 2 cups of fresh spinach into the sauce. Cook for 3-5 minutes until vegetables are tender.

Add the cooked ramen noodles and grilled beef to the pot, gently toss together. Cook for an additional 2-3 minutes.

Serve in bowls and garnish with sliced green onions.