i prefer to stuff mushroom caps with a lower fat meat, usually crab, and to use a bit more flavorful cheeses made as a blend with lighter cheeses, e.g., gouda, monterey jack, farmer's or chevre. mozerella gives a nice brownable topping that holds it all together, right on top. also, some added italian seasoned bread crumbs. you could also mix in a little egg with the seafood or meat. fatty meats don't work well with mushroom caps; they are too absorbent. and be sure not to get them wet when cleaning them or you will have a wet, soupy mess. mix in a little of the stems, cut up, and finely cut yellow onion and or celery.