Heat water to make broth, cook over high heat until boiling.
Heat sesame oil, sauté onions and shiitake mushrooms until browned.
Then add to boiling water along with other ingredients.
Cook until the water has reduced. Turn off the heat and strain.
Cut the tilapia fillets into cubes, add lime juice. Set aside.
Heat 5 tablespoons of onion oil, sauté the ground spices until fragrant.
Add some of the sliced green onions and the tilapia pieces. Stir gently.
Then add the fish sauce, Worcestershire sauce, salt, ½ teaspoon of pepper, sugar, seasoning, broth, and 3 tablespoons of sesame oil. Stir gently. Cook until the water has evaporated, then turn off the heat.
Boil the noodles in boiling water for 2-3 minutes, then remove and drain briefly.
Place the noodles in a large bowl, add soy sauce, ground pepper, onion oil,
sesame oil, and 50 ml of broth. Stir until well mixed.
Divide evenly into 2 bowls, top with tilapia, pak choy, mayonnaise, and scallions.
Prepare 2 more bowls, add a few scallion slices, then drizzle with broth.