Dashi Powder is the quickest way to make dashi as you can sprinkle the powder into soup and dishes while you’re cooking. There is no pre-cook time required.
Here are some MSG-free Dashi Powder packages:
This product called Hondashi (ほんだし) is widely available in Asian markets and sometimes American supermarkets (and it has MSG in it).
Watch this video to see how you use it.