Slice zucchini, onion, green onion, and spicy green chili.
Add perilla oil to a pot and stir-fry gochugaru (Korean chili flakes) over low heat.
Add 300ml of water and the prepared vegetables, then bring to a boil.
Once the broth boils, add the soft tofu and gently stir to dissolve.
Add perilla seed powder and season with salt.
Add green onion at the end and bring to a boil once more.