Make Dashi broth according to Dashi recipe. Or you can use an instant Dashi.
Slice onion thinly and cut broccoli into small pieces.
Boil onion and broccoli stems in the dashi for 5 minutes covered. Add the broccoli florets and eggs. Cover and cook for additional 2 minutes or until the eggs are cooked to your liking.
Dissolve miso paste in the soup.