Heat oil in a heavy bottom pot, and add celery, onion, carrot and a pinch of salt. Saute on medium flame until soft and golden brown. Add chopped garlic, ginger and chili flakes and saute for two minute.
Add tomato and cook for a minute. Add bell pepper, zucchini and mushroom and a pinch of salt. Cook for 3-4 minutes.
Now add the low sodium vegetable broth, handful of coriander leaves with the stem, water, sambal olek, and crushed black pepper and little salt (not too much, as we will be adding soy sauce later). Scrape the bottom and mix all the ingredients.
Bring it to a boil and reduce the heat to medium and simmer the soup for 15-20 minutes. Now add soy sauce, more sambal olek, sugar (optional) and lemon juice. Mix it well, taste and adjust accordingly.
The soup is done, now when you are ready to serve the soup add the frozen dumplings and simmer the soup for 5 mins. Add just the amount of dumplings you will be serving as they tend to get soft if they stay longer in the soup.
To serve laddle the soup into large bowls, add 3 dumplings for each serving. Add kimchi and drizzle with crunchy chili onion, and garnish with chopped coriander leaves.