01 - Set oven temperature to 180°C (350°F).
02 - Cook ramen noodles in boiling water for 2 minutes less than package directions. Drain thoroughly and set aside.
03 - Heat vegetable oil in a large skillet over medium heat. Add onion, garlic, and ginger; cook for approximately 3 minutes until fragrant and translucent.
04 - Add ground pork and cook until evenly browned, breaking up any large pieces with a spoon.
05 - Stir in gochujang, red pepper flakes, crushed tomatoes, soy sauce, rice vinegar, and sugar. Season with salt and pepper. Simmer the mixture for 10 minutes until slightly thickened.
06 - Combine ricotta cheese, egg, half of the shredded mozzarella, and half of the grated parmesan in a bowl. Mix thoroughly until uniform.
07 - Spread a thin layer of meat sauce on the bottom of a 22x30 cm (9x13-inch) baking dish.
08 - Arrange approximately one pack of ramen noodles over the meat sauce, trimming as needed.
09 - Evenly spread one-third of the ricotta mixture over the noodles, followed by one-third of the meat sauce. Repeat layering twice more, using all components, and finishing with the remaining meat sauce.
10 - Scatter the remaining mozzarella and parmesan evenly over the surface.
11 - Cover baking dish with aluminum foil and bake for 20 minutes.
12 - Remove foil and bake an additional 10 to 15 minutes until cheese is bubbling and lightly golden.
13 - Allow dish to stand for 10 minutes before slicing. Garnish with sliced green onions if desired.