Mix soup and soy sauce.
Layer half each of the beans, mushrooms, bean sprouts and soup mixture in 1 1/2-quart casserole; repeat.
Cover tightly and microwave on high (100%) 5 minutes; rotate casserole 1/2 turn.
Microwave until hot and bubbly, 5 to 8 minutes longer.
Sprinkle with chopped cashews.
Cover and let stand 5 minutes.