Bring a pot of water to a boil. Add in the cubed brisket. Simmer for 10 minutes, skimming the top of the water for scum. Drain the brisket and rinse any excess scum off.
Add the brisket back into the pot with 6 cups of new clean water. Bring to a boil. Skim off any remaining scum.
Add the onions, garlic, peppercorns, bay leaves, and salt. Cover. Reduce the heat to medium low and simmer for 2 hours.
Strain the broth. Set the beef aside. Discard the bay leaves. Keep the broth warm.
Mix 1 cup of the hot broth with the soy sauce and brown sugar. Set aside.
Heat up the cooking oil in a large sauté pan over medium high heat. Sauté the onions, garlic, and ginger for 5 minutes.
Add the brisket in. Sauté for 5 minutes.
Pour in the sauce. Toss in the star anise. Simmer for 10 minutes until the majority of the liquid has evaporated.