In a mixing bowl, combine 1 1/2 cups of Oreo cookie crumbs with 6 tablespoons of melted unsalted butter until the mixture resembles wet sand. Press this mixture firmly into a 9-inch tart pan, ensuring an even layer on the bottom and up the sides. Chill the crust in the refrigerator for at least 20 minutes, allowing it to firm up and set.

In a medium saucepan, heat 1 cup of heavy whipping cream over medium heat until it starts to simmer, being careful not to let it boil. Remove the saucepan from the heat and stir in 2 cups of finely chopped bittersweet chocolate and 1/4 cup of unsalted butter. Allow it to sit for a minute before stirring until the mixture is smooth and glossy.

Once the chocolate filling is ready, take the chilled Oreo crust from the refrigerator. Pour the luscious chocolate filling into the crust, using a spatula to smooth the surface evenly. Cover the tart loosely with plastic wrap and return it to the refrigerator for at least 4 hours, or until it’s set and firm enough to slice.

After chilling, remove the Smooth No Bake Chocolate Tart from the refrigerator and gently unclip it from the tart pan. Prior to serving, you can garnish with chocolate curls, fresh berries, or a dusting of powdered sugar for a touch of elegance. Slice carefully and delight in the deliciously creamy chocolate goodness.