Much of the flavor we associate with skillfully prepared food comes from the browning reactions that take place during cooking. In the case of sugary foods, this process is called caramelization. In high-protein foods, there is a different kind of browning called the Maillard Reaction. As proteins are altered by heat, they produce a complex range of flavors and aromas that make cooked food much more appealing than raw. Mushrooms contain sugars as well as proteins, so caramelization and the Maillard reaction both contribute to the taste of a cooked mushroom.
Here’s a story discussing how to maximize the Maillard reaction in your mushroom cookery. In a nutshell: use sufficient heat, avoid too much water in the pan, stir infrequently, and don’t crowd the mushrooms. You may have heard experienced chefs say that we often use too much butter (which contains a lot of water) and not enough heat for cooking our mushrooms; the Maillard Reaction is the reason why this is true.
With a non-stick pan, you can put the mushrooms in dry over medium-high heat to promote the Maillard reaction. Let them lie still with only occasional flipping or stirring, instead of constantly agitating them, and allow them to cook in their own juices. The fluid that “sweats” from the mushrooms will eventually dry to a dark crust in the pan, at about the same time the mushrooms themselves are obviously browned. You’ll think you’ve over-cooked them, but you haven’t. Add a dash of wine or sherry to deglaze the delicious crust from the pan, and reduce it down while stirring until almost dry again. And only then, late in the cooking process, add your butter or sauce for flavor.
Another Maillard-friendly alternative to cooking the mushrooms dry is to sauté them at length in clarified butter or ghee, which is butterfat with the water, protein, salt, and milk sugars removed. This will produce even more uniform browning, and some chewiness that you may or may not like.
Here’s a pic of this weekend’s porcini being cooked dry in the pan last night, showing some nice Maillard browning: