In a medium bowl, combine crushed Oreos and melted butter.
Transfer Oreo mixture to a 14×4-inch rectangular tart pan or a 9-inch round tart pan. Press into the bottom and halfway up the sides. Chill until ready to use.
In a blender combine tofu, peanut butter, melted chocolate, and milk. Blend for 4-5 minutes, or until smooth, scraping as needed.
Spread the tofu mixture over the chilled crust; chill for at least 1 hour or up to 24 hours. Cover if chilled for more than 4 hours.
Slice and serve. Garnish with an additional drizzle of melted chocolate, if desired.