Soak the shiitake mushrooms in hot water for 2 hours, or until mostly reconstituted. Rinse them well.
Heat a wok or pot over medium heat. Add the oil, bay leaf, ginger, and the white parts of the scallions. Fry until fragrant, about 1 minute.
Then add the garlic. Cook for another 30 seconds, and stir in the tomato paste, sugar, and salt. Cook until the oil has a deep red color, about 5 minutes.
Then add the broth or water (including any mushroom soaking liquid, being careful to avoid any grit from the mushrooms) along with the soaked shiitake mushrooms.
Bring to a simmer, cover, and let the soup simmer for 10 minutes. Add the scallion greens. You’re now ready for hot pot!
Video
Notes
Note: prep time includes mushroom soaking time. Actual active prep is more like 5 minutes.