Crush 9 Oreo cookies into crumbs in a food processor or blender. Set the crumbs aside in a bowl for sprinkling.
19.1 ounces Oreo cookies
Crush the remaining cookies to fine crumbs.
Add the Oreo crumbs and cream cheese to a large bowl and beat with a hand mixer until well combined.
8 ounces cream cheese
Chill the mixture in the refrigerator for at least 1 hour or in the freezer for at least 20 minutes.
Use a cookie portion scoop to gather about 2 tablespoons of the mixture at a time. Roll into balls.
Separate the semi-sweet and white baking chocolate into 2 bowls. Melt in the microwave according to package directions.
8 ounces semi-sweet baking chocolate, 8 ounces white baking chocolate
Using a fork, dip each Oreo ball into the melted chocolate, and let the excess chocolate run off the fork.
Place each ball on a lined baking sheet. Sprinkle some or all of the truffles with the reserved cookie crumbs.
Chill until firm.
Drizzle extra chocolate over the top of the truffles if desired.