Place packets of Kayanoya Original Vegetable Stock Powder, water, leek, and thinly sliced ginger in pot, bring to boil, and simmer for 2--3 minutes at medium heat. Remove dashi packets, add beef, and simmer at low heat while skimming broth. Flavor with fish sauce and salt.
Place boiled pho noodles, soup, red onion and beef in bowls in desired portions. Finish by adding herbs of your choice, red chili pepper, and lime.