Add olive oil, ginger, garlic, and Shiitake into a pot and slowly heat up and stir fry.
Once fragrant, add celery and 1 tsp of salt, then cook with the lid on until translucent. (low to medium heat)
Add the bay leaves, thyme, and Shiitake rehydrating liquid, and top up the pot to 4 cups of water.
Cook at medium heat, then add the tomatoes and a pinch of salt just before it starts to boil.
Finally, add salt and black pepper to taste.