1. Heat olive oil in a large pot over low heat. Add onions and salt, and sweat over low heat until onions become translucent, release liquid, and have mostly broken down, around one hour.
2. Add Thai chili paste, ginger and lemongrass; stir and sauté for two minutes. Add stock, coconut milk, soy sauce, and chili pepper. Bring to a boil, then reduce heat and simmer on low, uncovered, for approximately one hour. Discard ginger and lemongrass.
3. Add shiitake mushrooms and cook for an additional five minutes.
4. To serve: Add rice noodles, chicken, bok choy and roasted squash to a bowl. Pour broth over and finish with scallions, chili pepper, cilantro, mint, bean sprouts and lime wedge.