Use a food processor to finely crush the Cinnamon Toast Crunch (try to avoid having any larger pieces of cereal as they may taste stale once it's in the truffle). If you don't have a food processor, place the cereal in a gallon plastic bag and crush using a rolling pin.
Combine the cereal crumbs and softened cream cheese. Use a mixer or your hands to incorporate fully.
Use a mixer to mix in milk, cinnamon and powdered sugar. Mix until well combined, then scrape down the bowl once complete.