9-ounce) box instant chocolate pudding mix in a large bowl and whisk to remove any large clumps. Add 2 cups whole or 2% milk and whisk vigorously until thickened and no lumps remain, 1 to 2 minutes.Pour the pudding mixture evenly over the brownie base and smooth the top. Press a sheet of plastic wrap directly against the surface of the pudding. Refrigerate for at least 2 hours up to overnight.Garnish the pie:Chop or crush 4 Oreos until pieces no bigger than the size of a pea.When ready to serve, make the whipped cream. Place 1 1/2 cups cold heavy cream, 1/4 cup powdered sugar, and 1/2 teaspoon vanilla extract in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Beat with the whisk attachment on medium speed until firm peaks form, 2 to 5 minutes.Spoon the whipped cream evenly on top of the pie and smooth into the top with an offset spatula. Garnish with the crushed oreos and 2 tablespoons chocolate curls if using. For the pie pan, slice and serve straight out of the pan. For the springform pan, run a knife or small offset spatula around the pie, then release and remove the ring before slicing
