Make the brownie mix according to the box instructions.
Fold in chopped Toblerone pieces. Pour into a greased pan (edge brownie pan if using) and bake according to box directions—or about 30 minutes for the edge pan. Let cool completely.
In a chilled mixing bowl, whip heavy cream until stiff peaks form.
In a separate bowl, beat cream cheese, powdered sugar, vanilla, and pudding mix until smooth.
Gently fold the whipped cream into the cream cheese mixture until fluffy and combined.
Stir in the crushed Oreos.
Spread or pipe the Oreo frosting onto cooled brownies. Refrigerate for at least 1 hour before slicing and serving.