Place the cooking fat, garlic, ginger, scallions, and chili sauce in a dutch oven or large pot and cook over medium high heat for 2-3 minutes, until fragrant and the scallions start to soften.
Add the chicken stock, beef broth, fish sauce, and soy sauce and bring to a boil over high heat. Taste and adjust as necessary (I add about a cup of water to reduce saltiness).
Add your eggs, if cooking, and the noodles to the boiling soup, and cook for about 3 minutes (the noodles I use require about 3 minutes, but follow the package instructions).
Serve and enjoy!
