It's worth the time
Dashi is a Japanese soup stock. This vegan version of dashi made from shiitake mushrooms and kombu seaweed will give you a gentle, mild umami flavor packed with a significant amount of natural vitamin D.
I'll be upfront in saying the way I did this recipe for homemade vegan dashi is for those who want to go the extra mile to get additional natural vitamin D...which in my opinion is worth taking the time.
This recipe will take about 2 days which indeed sounds like a lot of time but it will make total sense, and again will be worth it. This recipe is also optimally done when you have access to maximum direct sunlight exposure like in Spring and Summer.
For quick to make dashi
If you want to make vegan dashi fast, here is a great recipe for "Vegan Shiitake and Kombu Awase Dashi," by Sudachi Recipes that takes 40 minutes to make.
A cool fact about vitamin D and mushrooms
When mushrooms are exposed to direct sunlight with the gills up, they will behave like solar panels and create high levels of vitamin D2 from the sun.
From this Cooking Light article, "No One Gets Enough of This Depression-Fighting Vitamin, but a Crazy Mushroom Technique Could Change That,"
"Paul Stamets, a mycologist, author, and founder of Fungi Perfecti, notes a study he conducted during the summer in Washington state.
He found that shiitake mushrooms dried outdoors in 6 hours of sunlight over two days had more vitamin D when they were dried with their gills facing up—they went from 100 IU per 3.5 oz to nearly 46,000 IU!"
That's some serious next level vitamin D creation!
This is why I think it's worth the 2 days to get fresh shiitake mushrooms and dry them yourself in the sunlight to get that enormous amount of natural vitamin D in your mushrooms.
And the good news is that you can dry extra amounts of shiitake mushrooms while making the amount needed for this dashi recipe, and then store your newly dried vitamin D packed shiitakes and use later when you want.
From the Walmart website, here's an example of what 3.5 oz of fresh shiitake mushrooms looks like.
For maximum sunlight exposure, slice the mushrooms in pieces which will provide more surface area for exposure to sunlight.
I bought fresh whole shiitake mushrooms at an Asian market, and then sliced them up either in half or in thirds depending on how large the mushroom was.
I did 2 days of 5-hours each day for mushroom drying from 10am - 3pm in direct sunlight.
I only did 5 hours primarily because it was winter with shorter daylight hours. As I mentioned before, the best time to dry shiitakes to get the max amount of vitamin D you can get is when the sunlight is most optimal during Spring and Summer.
My shiitakes didn't dry to the point where they were like rock hard, but they were hard-ish...which was fine for me.
Making the Dashi
For baseline, I used this recipe for "Shiitake and Kombu Dashi (Japanese Vegan Dashi)" by Chef JA Cooks. Her post goes into some wonderful education about different varieties of shiitake mushrooms and varieties of kombu and the types of flavor profiles you'll get with each.
Dried Shiitake mushrooms - 4 whole mushrooms
Dried Kombu seaweed - 5"x7" piece cut into 3 strips
Spring water (to fill the jar)
Save pasta sauce jars. I used a 28 oz Rao marinara sauce jar to make the dashi.
Put the mushroom pieces, kombu, and water in a glass jar, then put the jar with closed lid in the fridge and let it soak for over 5 hours. Leave a little room at the top of the jar because the mushrooms will expand during soaking and will take up more space.
Another option: Prepare your dashi at night and let it soak in the fridge overnight.
The dashi is ready when you see the stock is a nice golden brown. Use a strainer to separate the dashi stock from the mushroom pieces and kombu.
Save the mushroom pieces and kombu because you can still eat them.
Volia! You now have homemade dashi packed vitamin D.
This fresh dashi can be used for 3-5 days stored in the fridge, or you can freeze it and use it up to one month.
With the leftover shiitake mushroom pieces and kombu, you can use them to make foods like miso soup, or chop them up to use in fried rice or a ramen topping.
Use dashi to make vegan Oyakodon
What inspired me in the first place to make vegan Dashi was wanting to make some vegan Oyakodon which calls for dashi in the ingredients.
I thought it would be fun for my first time to make homemade vegan dashi. I was up for the challenge. So glad I did! Here's my recipe for vegan Oyakodon.