01 - Set oven temperature to 350°F (180°C) and allow to fully preheat.
02 - Cook ramen noodles in a large pot of boiling water for 2 minutes less than package instructions. Drain thoroughly and set aside.
03 - Heat vegetable oil in a large skillet over medium heat. Add chopped onion, minced garlic, and grated ginger. Sauté until fragrant and onion turns translucent, approximately 3 minutes.
04 - Add ground pork to the skillet and cook until browned, breaking up the meat with a spoon as it cooks.
05 - Stir in gochujang, red pepper flakes, crushed tomatoes, soy sauce, rice vinegar, and sugar. Season with salt and pepper. Simmer for 10 minutes, stirring occasionally, until the sauce thickens slightly.
06 - In a mixing bowl, combine ricotta cheese, egg, half the mozzarella, and half the parmesan cheese. Stir until homogenous.
07 - Lightly grease a 9x13-inch (22x30 cm) baking dish. Spread a thin layer of meat sauce at the bottom. Arrange one pack of ramen noodles over the sauce as the first layer.
08 - Spread one-third of the ricotta mixture over the noodles. Add one-third of the remaining meat sauce on top. Repeat layering noodles, cheese mixture, and meat sauce twice more, finishing with meat sauce on top.
09 - Sprinkle remaining mozzarella and parmesan cheese evenly over the lasagna.
10 - Cover baking dish tightly with aluminum foil. Bake in preheated oven for 20 minutes.
11 - Remove foil and continue baking for an additional 10 to 15 minutes, until cheese is bubbling and lightly golden.
12 - Allow lasagna to stand for 10 minutes before slicing. Garnish with sliced green onions if desired.