1 pound Cremini or white button mushrooms
4 teaspoons unsalted butter
1-1/2 teaspoons kosher salt
Find a colander that fits almost completely into a bowl. Place the mushrooms in the colander, put it into the bowl in the sink, and fill with water. (Or, if you have a salad spinner, you can put the mushrooms in the basket inside the bowl and fill the bowl with water). Let them soak for a few minutes, swishing them around with your hands if necessary to get them clean. Lift the colander out of the bowl and drain the mushrooms.
Trim the stems off and quarter (or slice) the mushrooms. Put them into a sauté pan – you want to crowd the mushrooms, so pick a pan that causes the mushrooms to stack up two- or even three-deep. Add enough water to the pan to make the mushrooms float. Add the butter and salt, and set over high heat.
When the water comes to a boil, reduce the heat to maintain a very high simmer (aka low boil). Stir in the butter when it melts.
Cook, stirring occasionally, until all the water evaporates. You don’t have to pay too much attention, because you’ll hear them start to sizzle. Once all the water is gone, brown the mushrooms in the butter that remains.
If you want to add any seasoning to the mushrooms, now’s the time. You can toss in some minced garlic, or deglaze the pan with sherry or wine, or both.
Use as directed.