1 package (about 36) whole Oreos
1 cup (16 tablespoons) butter, divided
2/3 cup packed brown sugar
1 1/4 cup heavy whipping cream, divided
1 (12 oz) bag dark chocolate chips
Finely crush the Oreos with a food processor or blender. Stir crumbs together with 8 tablespoons melted butter until well combined. Press into the bottom and sides of a pie pan. Freeze crust for 10 minutes until set.
Combine remaining 8 tablespoons butter and brown sugar in a small saucepan. Cook over medium heat, whisking constantly, until mixture begins to bubble. Continue cooking, whisking constantly, for 1 minute. Remove from heat. Slowly whisk in 1/4 cup heavy whipping cream until smooth. Cool caramel about 15 minutes. Pour the caramel over the Oreo crust, then return to freezer for about 30-45 minutes until just chilled and set.
Place chocolate chips in a glass bowl. In a saucepan, bring 1 cup heavy whipping cream to a simmer over medium-high heat. Pour the cream over the chocolate chips and let sit for 5 minutes, then whisk until completely smooth. Pour the chocolate over the caramel and freeze for a final 30 minutes, until just chilled and set. OR refrigerate, covered, until ready to serve.