We collect local mushrooms each year to last use until the next season. These are mainly chanterelles and boletes. Before we put them in the dryer we wash/dry them. Because they have already absorbed as much water from the atmosphere as they could when they were growing the short water bath doesn't effect them. (See A. Brown on washing mushrooms). After the mushrooms have thoroughly dried until they resemble leather we put them in a food processor and 'blitz' them until they are about the size of a 'sweetlet' pea. Then we put them in small mason jars and put them in the freezer. They last for months this way and the taste is VERY intense so just a pinch in a stew or whatever goes a long way. We don't reconstitute them because we want them to be little 'flavor sponges'.
Ever seen a plate of spongy soggy slimy looking sautéed mushrooms. Yes? The biggest misconception about sauteing mushrooms is most cooks heat a pan then add some butter then throw in the mushrooms and brown them. By the time the mushrooms have given up their moisture and replaced it with the butter they are soggy and over cooked. Don't do that. Instead add the sliced/whole/diced mushrooms to a warm saute pan. Slowly raise the heat just so the water in the mushroom starts to accumulate in the pan. Don't overcrowd the pan or this technique will not work. You'll be surprised at how much water there will be. Wipe out this water with a paper towel. Now the mushrooms are not over cooked but they have lost a lot of water. NOW add a pinch of butter and a couple of drops of the best olive oil you can afford and a pinch of nutmeg if you like. Now turn the heat up full whack until the mushrooms have absorbed the butter/ oil. Remove and serve on a nice piece of toasted 'red fife' bread.