Add 1-2 tablespoon of avocado oil and sauté the chopped yellow onion over medium heat until softened, about 2-3 minutes.
Stir in the minced garlic and ginger, cooking for another 30 seconds until fragrant.
Pour in 8 cups of water and add the chicken bouillon, rice vinegar, sesame oil, and soy sauce. Stir to combine and bring the soup to a gentle boil. Simmer for 30 minutes. While soup simmers, make filling.