Slice the lemongrass. Cut off the green part of the lemongrass stalks and discard it. Mince one stalk and slice the remaining three stalks in halves. Slightly crush the halved lemongrass stalks using a cleaver or the side of a large knife. This will help release the natural oils of the lemongrass.
Sauté the aromatics. Heat a tablespoon of oil in a saucepan over medium heat. Once hot, add the minced lemongrass and ginger, and sautée for about 1 minute.
Add the mushrooms. Next, add the mushrooms and sauté for another 3-5 minutes.
Cover with water. Pour in water, salt, and maple syrup. For extra lemongrass flavor, add the crushed lemongrass stalks. Simmer covered for about 15 minutes. At the end of cooking, stir in the lime juice and adjust the seasonings to your liking.
Serve. Serve the broth piping hot with fresh cilantro and a crack of ground black pepper! This soup will keep for up to 4 days in the refrigerator.
Notes
Use fresh lemongrass. For optimal flavor, ensure you use the freshest lemongrass stalks. The leaves should be green and firm. Avoid stalks that have a brownish color or a dry texture.
Double the recipe. This broth yields two servings, so I highly recommend doubling the recipe if you want to enjoy leftovers as a noodle soup. Check out the optional add-ins below for ideas!