Miso soup! I know this isn't Korean food but it's milder than dwen jahng chigae and good for you. This is my kids favorite soup. They love the seaweed and tofu in it. I add rice to the soup to make it more of a meal. Great for babies starting solids....just make sure you cut up the wakame seaweed into small pieces. Most asian markets sell it already cut up so less work for you!
I found this video on how to make it.
How To Make Miso Soup