Beans: Rinse mung beans with cold water in a colander, picking out any bad looking beans or pebbles. Add beans to a large pot along with vegetable broth. Set heat to high and bring to a boil. Reduce heat to reach a gentle simmer, then cook the beans, uncovered, for 30 to 40 minutes. They are finished when they are soft and some have burst. Most of the water should be absorbed, though a little is okay.
Flavor Makers: While mung beans cook, heat oil in a large sauté pan over medium heat. Add onion, garlic, ginger, and celery. Cook until onion is soft and translucent, about 5 minutes.
Soup: Add sauteed veggies into the pot of mung beans, along with the can of coconut milk and chopped spinach. Let gently simmer until coconut milk is hot and spinach has wilted. Serve warm.
Store in an airtight container in the fridge for 5 to 7 days.
Find mung beans in the international or dried beans aisle, or check an Asian supermarket.