Step 1

Soak the dashima and shiitake mushrooms for about 30 minutes in a large pot with 10 cups of water. You can skip soaking if you don’t have time, but soaking maximizes the flavor of the broth.

Step 2

Add the other vegetables you're using to the pot.

Step 3

Bring it to a boil over high heat and boil, covered, for 10 minutes. Remove the dashima. Reduce the heat to medium, and continue to boil, for about 20 minutes. Turn the heat off. Let the broth cool.

Step 4

Pour the broth through a strainer into a large bowl. Press the vegetables with a spoon or spatula to squeeze out any remaining broth.

Step 5

Store the broth in the fridge up to a week, or in the freezer up to 2 months.