Add all of dipping sauce ingredients to a saucepan (30 g Japanese leek (naganegi), ½ tsp grated garlic, ½ tbsp grated ginger, ½ tsp dashi granules, 1 tbsp Japanese soy sauce (koikuchi shoyu), ½ tbsp oyster sauce, ½ tbsp Chinese-style chicken bouillon powder, 2 tbsp mirin, ½ tbsp rice vinegar, 1 pinch ground black pepper, 1 tbsp toasted sesame oil, 1 tsp toasted white sesame seeds, 250 ml water) and bring to a boil. Simmer for 2-3 minutes, then turn off the heat and leave to cool.
Bring a pot of water to a rolling boil and add 2 ptns ramen noodles. Cook for the time stating on the package instructions.
Once cooked, drain the noodles in a colander and then rinse with cold running water. Place the colander with noodles in a bowl of cold water and add a few ice cubes to chill further.
Add about 5 ice cubes to the dipping sauce to chill.
Drain the noodles once more and place them on a zaru (or on a sushi mat over a bowl to allow excess liquid to drain). Serve with pork chashu, seasoned bamboo shoots (menma), ramen eggs or your choice of toppings and sprinkle with kizami nori (shredded nori) and finely chopped green onions.
Divide the dipping sauce into individual serving cups, dip your noodles and enjoy!
Notes
Chicken bouillon powder varies by brand. My brand is 1 tsp per 200 ml, so if yours is more concentrated (e.g., 1 tsp per 300 ml or 1 cup), use touch less to avoid oversalting.