How to Sautee Mushrooms?

Melt about 1/2 cup butter in a iron skillet, add mushrooms and about 1/2 cup chopped up onion. Let cook for about 10 minutes over medium low heat, add about 1/2 to 3/4 cup of soy sauce and cook for another 10 minutes or so. Just before removing from heat, add 1/2 to 3/4 cup of shredded parmesian cheese.