Place a glass bowl over a medium saucepan filled in 1-inch of water. Bring the water to a simmer over medium-low heat. Place the white chocolate chips in the bowl and melt, stirring occasionally. (Do not overheat chocolate or it will seize.
Line a 9-inch x 9-inch baking dish with waxed paper. Pour half of the melted chocolate into the dish and spread into an even layer. Transfer the baking dish to the freezer to let the chocolate harden. Return the melted chocolate in the bowl back over the simmering water.
Place the Oreos and cream cheese in a food processor. Pulse until cookies break down, using a spoon or rubber spatula to stir things around as needed. Process the truffle mixture until smooth and evenly combined.
Remove the baking dish from the freezer. Add the truffle mixture on top of the hard chocolate and spread into an even layer. (I spray a hand with cooking spray and use that to spread the truffle mix.)
Pour the remaining white chocolate over the truffle mix and spread evenly over the top. Sprinkle candy corn (whole or chopped up) all over the white chocolate.
Refrigerate for 1-2 hours to let the chocolate and truffle mix set up. Remove the candy from the pan, pull off the waxed paper, and use a knife to cut the candy into good-sized pieces. Store in the fridge.
Notes
If you'd like to make candy corn colored truffle bark, substitute Golden Oreos for chocolate and make these changes.
Add orange gel food coloring to Golden Oreos once truffle filling is mostly completely blended in food processor. You may need to use a rubber spatula to help color the truffle filling evenly. Add more food color as needed to reach a vibrant color.
To the remaining half of the melted white chocolate chips, add yellow food coloring until a vibrant color has been reached. Pour this on top of the truffle filling layer.
Now you'll have white, orange, and yellow layered truffle bark with candy corn on top. :)