Preheat oven to 350 degrees.
Using a large bowl, beat together until combined the cake mix, eggs, water, and oil. Fill cupcake liners 2/3 full with the batter. Put them in the oven and bake for 22 minutes.
Cut brownies into squares. Pipe small dollops of frosting onto the brownies. Pile on broken mini pretzel twists.
Pipe a ring of frosting onto the top of the cupcake. Carefully place the brownie on top of the frosting.
Drizzle chocolate sauce on top and then plate them up!