Preheat broiler. Remove stem from tomatoes and slice in half lengthwise. Place tomato halves cut side up in an 8x8-inch metal pan or on a baking sheet. Set aside. Squeeze as much moisture as possible from thawed spinach. Place in a medium mixing bowl. Add next 8 ingredients (bread crumbs through pepper) and blend well. Lightly press mixture over cut side of tomato halves. Spray lightly with butter-flavored cooking spray. Broil 6 inches from heat for 3-5 minutes or until topping is lightly browned. Serve immediately.