1Heat oven to 350°F. Grease bottom only of 13x9-inch pan with shortening or cooking spray. Make brownies as directed on box for 13x9-inch pan.
2Bake 25 minutes. Sprinkle with marshmallows; bake about 5 minutes longer or until marshmallows are puffed and golden. Sprinkle with candies.
3In small microwavable bowl, microwave chocolate chips and shortening uncovered on High 15 seconds; stir. Drizzle over brownies. Cool completely, about 1 hour. For easier cutting, use plastic knife dipped into hot water. For brownies, cut into 6 rows by 4 rows.