Make the Sauce Base: In the bottom of two large, deep serving bowls, aggressively whisk together the soy sauce, melted pork fat (or sesame oil), oyster sauce, and sugar. This is the rich, oily base of the dish.

Cook the Noodles: Boil the thick ramen noodles according to the package directions until chewy and al dente. Drain them incredibly well, shaking off all excess water.

Assemble the Bowl: Immediately transfer the piping hot noodles into the bowls, placing them directly on top of the dark sauce pool.

Add Toppings: Arrange the Chashu pork slices, chopped green onions, and Nori seaweed beautifully around the noodles. Carefully drop a single, vibrant raw egg yolk into the exact center of the bowl.

Mix and Eat: Drizzle the rice vinegar and chili oil (Rayu) over the top. To eat, use your chopsticks to break the yolk and aggressively mix everything in the bowl together from the bottom up. The hot fat, soy sauce, and egg yolk will emulsify into an unbelievably rich, creamy sauce that clings to every noodle.