1Place stock in a large pot over high heat. Add the minced lemongrass (and leftover lemongrass stalks, if using fresh lemongrass), plus lime leaves. Bring to a boil.
3When soup reaches a bubbling boil, reduce heat to medium, or until you get a nice simmer.
5Add the garlic, galangal, chilli, mushrooms, lime juice, fish sauce and soy sauce. Stir well and simmer 3 minutes.
7Add the shrimp plus other vegetables, if using. Simmer until shrimp are pink and plump (about 3 minutes).
9Reduce heat to medium-low and add the coconut milk if using. Balance the taste with salt, sour and spicy. Add spoon of sugar.