Add the chicken stock to a medium pot or soup pot.
Add the whites of the scallions (keep the green parts for garnish later), smashed garlic cloves, sliced fresh ginger, soy sauce, and fish sauce to the chicken stock.
Bring the mixture to a simmer over medium heat and let it cook for about 10 minutes.
While the broth is simmering, bring a separate pot of water to a boil over high heat, then add the wontons to the boiling water.
Cook the wontons until they float to the surface. This usually takes about 4-5 minutes for frozen wontons and a bit less for fresh ones.
Once the wontons are cooked, use a slotted spoon to transfer them into individual serving bowls to ensure that any excess water is drained away.
After the broth has simmered and is richly flavored, pour it into the bowls through a strainer to remove the solids, leaving a smooth, aromatic broth.
Slice the remaining green parts of the scallions and sprinkle on top of the bowls.