Heat up the oil in a large pot then aff the ginger, garlic, and onions.
Sauté the vegetables until the onion becomes translucent.
Add the mussels and sauté for one more minute.
Pour in water. If you want more soup, you can add more.
Bring the soup to a boil, then lower the heat and let simmer until the shells have opened.
Season the mixture with fish sauce until you get you're preferred flavoring.
Add the sayote slices and let the soup simmer for a minute.
Add the chili leaves then cover and turn off the heat.
Scoop the soup into a bowl and serve it fresh.