Various mushrooms on a wooden cutting board next to a knife
The Reason You Should Let Mushrooms Sit In The Sun Before Cooking Them
On their own, 100 grams of white raw mushrooms contain about 7 IU (International Units) of vitamin D, but you can multiply that amount by letting your mushrooms sit in the sun.
A study published in Nutrients found that after just 15 minutes in the midday, mid-summer sun, the vitamin D content in sliced mushrooms jumped up to 700 IU per 100 grams.
After one hour, the fungi contained a whopping 1,300 IU of the nutrient. The recommended amount of daily vitamin D for adults is only 600 IU.
To reap the benefits of vitamin D-packed mushrooms, simply clean your mushrooms, slice them, and spread them out in a single layer on a baking sheet.
Place them outside in the sun between 10 a.m. and 4 p.m., when the sun's rays are the strongest. Try to leave them out in the sun for an hour to maximize nutritional value.
During this time, a chemical in your mushrooms called ergosterol will react with UV rays to generate and soak in even more vitamin D.