Preheat oven to 350 and grease a 9x13 baking pan with cooking spray and set aside.

In a mixing bowl, add cake/cookie mix, melted butter and egg. Mix well. The dough will be stiff and take a minute or two of mixing to come together. Press firmly into prepared pan. Bake 12-14 minutes or until center is set. Let cool.

Add butter and marshmallows to a large saucepan and heat on medium low heat, stirring constantly until marshmallows are melted. Stir in pumpkin pie spice and pumpkin baking chips. Stir until completely melted.

Remove from heat and stir in cereal and mix well to coat evenly. Spoon cereal on top of crust and gently press into the pan.

Top with M&M candies. Heat chocolate chips in a microwave safe bowl for 1 minute on 50% power. stir until completely melted, returning to microwave if necessary until melted. Drizzle onto the top of the cookie bars. Let set to harden.

Cut into 2" bars. Makes 36 bars.