Prepare the ingredients such as beef, onion, bean sprouts, and cilantro.
Boil the pho noodles in hot water for 3 minutes, then rinse in cold water.
Add water to a pot and simmer the beef and onion to make the broth.
Strain the broth using a sieve to make it clear.
Place the cooked noodles in a bowl and top with beef, bean sprouts, onion, and cilantro.
Pour in the broth and garnish with lime, chili peppers, and herbs as desired.