Here is something I do to get mushrooms to release water so I can cook with them: This works for mushrooms sliced, hand chopped, or chopped to a fine "grain" in the food processor. I put them in the dry skillet and stir constantly while cooking over a medium-high flame. In less than 5 minutes, depending on the amount of mushrooms, they will start releasing water. When they look like they have released enough water, remove them from the skillet. Yes, your skillet will get cooked-on mushroom residue, but that is easily cleaned with water while the skillet is still hot. And the mushrooms are removed, of course. I use an iron skillet.