Wash and slice mushrooms. Dice onion. Cut yam into 1-inch pieces. Place mushrooms and onions in a pan sprayed with PAM, cover, and sautee over medium-high heat, stirring occasionally for about 5 minutes. Add all spices and reduce heat to low-medium. Add the yam pieces and cook 5-10 minutes, stirring occasionally and adding a little water if it gets too dry. Cook until the yam is just getting tender and all of it is moist but not watery.