Line a cookie tray with parchment paper or wax paper.: The scent of clean paper and the smooth, nonstick surface gives you a secure spot for setting truffles, and it prevents them from adhering as they cool. I always test one truffle first to ensure it comes off easily, because if the lining is oily or wrinkled the truffles can stick and break their coating. A common mistake is using an unlined tray which can cause chocolate to fuse to metal.
Place the Oreos (wafers and filling) in a food processor and pulse until they're fine crumbs.: Right away you will notice a deep chocolate aroma as the cookies break down, and the texture should go from chunky to sandy. The fine crumb ensures the mixture blends smoothly with the cream cheese , creating an even consistency. If you stop too soon you will have large bits that make rolling difficult, so process until nearly powdery but not paste like.
Using a stand or handheld mixer, beat the cookie crumbs and cream cheese until there are no lumps of cream cheese.: As you mix, you will see the crumbs absorb moisture and become glossy, and the bowl will emit a faint tang from the cream cheese . The right texture is cohesive and slightly tacky, not wet or greasy. If you rush this step you may end up with streaks of cream cheese, so scrape the bowl often to ensure uniform blending.
Form the mixture into round balls a little smaller than a golf ball (makes about 24 total). Place on the lined cookie sheet and freeze until firm (about 20-30 minutes).: When you roll, the dough should hold its shape and feel cool in your hands, with a compact, even surface. Freezing firms the centers so they will withstand dipping without collapsing. Avoid making balls too large because they take longer to chill and the centers might soften during coating.
Melt the chocolate candy melts according to package instructions.: As the candy melts liquefy you will see a glossy, viscous texture and a sweet, floral aroma. Stir slowly to achieve a uniform shine and avoid overheating which can dull the finish. Overheating is a frequent issue that causes graininess, so use short bursts of low heat or a double boiler for control.
Using a fork or candy dipping tool, dip each ball in the melted chocolate and place back on the baking tray. You want the truffles to stay cold and firm as you do this. So if they start to soften, pop them back in the fridge to harden again.: When you dip, listen for a faint tapping as excess chocolate drips off, and look for a smooth, even coat that covers the truffle without gaps. Work quickly but gently so the truffles stay cold. If a truffle softens or loses shape, chill it again before continuing, because dipping soft centers will create uneven shells and drips.
Optional: melt the white chocolate candy melts. Then drizzle the melted chocolate over the top of each truffle. Use the 1/2 cup of Oreo crumbs to sprinkle on the top of the balls before the coating sets.: The drizzle adds visual contrast and a second flavor layer while the crumbs give texture. Apply the drizzle in a fluid motion for thin ribbons, and sprinkle crumbs immediately so they stick to the tacky surface. A mistake here is waiting too long to sprinkle when the coating has already hardened.
Place the truffles in the fridge to harden for 1 hour.: In the refrigerator you will hear a quiet hum and see the coating take on a firm, glossy snap as it sets. Chilling stabilizes the shell and improves slicing or packaging behavior. If you try to eat them too soon the coating may smudge and lose its crispness.
Store truffles in an airtight container in the refrigerator for up to 7 days.: Proper storage preserves texture and flavor, and keeping them cold maintains the crisp coating and creamy interior. Place parchment between layers to avoid sticking and check the container for excess moisture. Leaving them at room temperature can cause softening and a loss of structural integrity.
