Ideally, this ramen is best eaten immediately after cooking. There is risk of the milk splitting when reheating the leftover soup unless you are using full-fat coconut milk. That being said, you can store the spicy miso soup in a sealed airtight container in the fridge for up to 2 days if needed. Cook the noodles when ready to serve and reheat the broth over medium heat in a pot on the stovetop until hot throughout. Be careful to not let the broth boil rapidly when reheating. Do not store the noodles and soup together in the fridge as the noodles will absorb the soup and bloat over time.