Put stock, soy sauce, garlic, and onion in a large stockpot and bring to a boil over medium heat.

Meanwhile, char ginger on all sides over an open gas flame or in a small skillet. Add to the stock.

Add the cinnamon sticks, star anise, and bay leaves to the broth.

Reduce the heat to low.

Simmer, partially covered, for 20-25 minutes.

Remove solids with a slotted spoon or strain the broth through a fine-mesh sieve.

Adjust seasonings if necessary.

Return to pot and keep hot until ready to use in soup.