Place pork tenderloins in (12 x 8-inch) baking dish.
Season with salt and pepper.
Place butter in mixing bowl.
MICROWAVE on HIGH until butter melts.
Mix in onion, pineapple and juice, soy sauce, ginger and bread crumbs.
Spread mixture over tenderloins MICROWAVE 35 to 40 MINUTES on '6' or until meat is fork tender, or internal temperature registers 185°.
For ovens without solid state heat control, MICROWAVE 42 to 48 MINUTES on '5'.