Place the chopped chocolate in a microwave safe bowl. Heat in microwave for 20 seconds on HIGH, stir, and heat again as necessary in 20-second increments until completely melted. Stir in the pumpkin pie spice and food coloring, if using, until completely blended.
Immediately pour melted candy over cereal and stir gently to coat.
Pour cereal into a large zip-top bag or large container with a tight-fitting lid and add the sprinkles (if using). Shake until all of the sprinkles are dispersed evenly.
Add the powdered sugar to the cereal and shake again until everything is coated. Spread onto baking sheet lined with foil or parchment and allow to cool. Discard excess powder. Store in an airtight container at room temperature up to one week.
Do not usewhite chocolate chips: If you can find them, Wilton pumpkin spice candy melts or pumpkin spice Hershey's Kisses also work here. Omit pumpkin pie spice and coloring and follow the same instructions.
Pumpkin pie spice: If you don't have pumpkin pie spice, use 1 teaspoon ground cinnamon, ¼ teaspoon ground nutmeg, and ¼ teaspoon ground ginger.
Sprinkles: nonpareil sprinkles are optional, but add a fun festive touch and crunchy texture. I have also used add-ins such as mini cinnamon chips, pepitas, sunflower seeds, or festive m&ms.