For the broth:
- Heat a large 10-quart soup pot over medium heat. Add the olive oil and when it is hot add onions, garlic, ginger and jalapeno and cook until soft and they begin to color, about 4 minutes. Add remaining spices and cook another couple minutes.
- Add broth, soy sauce and chicken thighs to the pot and bring to a boil. Immediately reduce to low and simmer for about 20 minutes until the chicken is done. Chicken can be removed when its internal temperature reads 155 degrees. The chicken will continue to cook and reach 165 degrees after they have been removed from the broth. Remove chicken and set aside to cool. When cool enough to handle shred into bite-sized pieces and set aside or refrigerate until ready to finish the soup.
- Strain the broth through a strainer and return to the pot. Skim any extra fat off the top. Or, if you are cooking the broth the day before, refrigerate overnight and the fat will rise to the top, coagulate and be very easy to skim off.
For the onions:
The caramelized onions can be made the same day as the broth or a day or two before or after. Caramelize no more than 3 – 4 onions in a pot at a time. If you have multiple appropriate pans you can caramelize them all at once.
- Heat a heavy-bottomed pan, such as a Dutch oven or cast iron skillet. Add olive oil. ghee or mixture of the two to the pot. Heat oil and add onions and generous pinch of kosher salt. The salt helps to pull the water out of the onions and begin the caramelization process.
- Lower the heat to somewhere between medium and low — low enough for your onions to cook slowly, without burning. Stir frequently in the beginning, scraping up any bits that begin to color and stick to the bottom. When the pan becomes dry and the onions start to stick, add a splash of wine or chicken broth to deglaze the pan. The liquid will create steam that will help release the onions. Give the pan a good scrape with a wooden spoon to release any stuck bits. Feel free to deglaze as needed.
- Continue cooking and stirring until the onions are golden brown, about 40 minutes.
Putting it all together:
- Combine the broth with the shredded chicken and the caramelized onions. Season with the rice vinegar to taste. Bring to a boil and immediately reduce heat and cook to combine flavors, about 15 minutes.
- Cook the noodles to package instructions and drain. Place the noodles in the bottom of oversized soup bowls and add broth to each bowl.
- Garnish with green onions, lime squeezes, sriracha and garnishes of your choice.