I recommend roasting them for about 15-20 minutes at 400 degrees with about 1/4 stick of butter or about 2 tbs. of olive oil for about a pound of wild mushrooms. Keep an eye on them while they cook and stir them occasionally, so that they don't burn. I personally like my mushrooms to be a little crispy and golden brown! I recommend not washing your mushrooms, instead just lightly brush them off with a towel. Also wait to salt the mushrooms until after they cook.