Trimming and slicing mushrooms are worth the effort because of the flavor they impart. Whole mushrooms need some cleaning and trimming — and slicing if the recipe calls for it.
Gently wipe away dirt from the mushrooms.
Use a damp paper towel or a dish towel.
Cut off the mushroom stems.
The stems typically aren’t eaten.
Place the mushroom caps, flat-side down, and slice them perpendicular to the cutting board.
This technique gives you strips of mushroom at whatever thickness you cut them.
If you want smaller pieces of mushroom, slice the caps again at a 90-degree angle from the original slices.
You can use these smaller chunks in soups and sauces, for example.