In most instances, we — food writers, cookbook authors and anyone else who tries to teach people how to cook — encourage people to salt at the beginning of the cooking process. Doing so gives the salt time to work its way into various ingredients, seasoning them throughout as opposed to just on the surface. But with mushrooms, this is the exact opposite of what cooks should do.
Mushrooms are 80 to 90 percent water, so adding salt at the beginning of cooking can cause them to release that liquid, which inhibits browning. (While we’re on the topic of moisture, it’s mostly a myth that you shouldn’t rinse or soak mushrooms in water. In reality, most varieties — except for those such as morels, lion’s mane and matsutake mushrooms — absorb a minuscule amount of water.)
In addition, early salting can adversely impact texture. “In order to preserve the texture of mushrooms, wait to add salt until they’ve just begun to brown in the pan,” cookbook author Samin Nosrat wrote in “Salt Fat Acid Heat.”
Here’s a simple breakdown of how to cook mushrooms — on the stovetop or roasted in the oven: Wash them to get rid of any surface dirt; cut or slice them, as desired; add them to a hot, preheated pan, with or without oil (it’s not necessary) and being careful not to crowd them too much (though a little bit is fine) as that can inhibit the moisture they release from evaporating; only add salt once the mushrooms have begun to brown; proceed with the rest of the recipe.