In a large pot, heat the oil over medium heat. Add the onion and cook for 4 minutes or until softened.
Add the garlic and ginger. Sauté for 1 minute until fragrant.
Add the broth and water. Increase heat to high and bring to a boil.
Stir in the soy sauce, Sriracha, and rice vinegar.
Add the rice noodles to the pot. Allow the noodles to sit in the broth for a few minutes, until softened.
Garnish with optional toppings, if using. Serve immediately.
