2 cups dark chocolate mini pretzels coarsely chopped
Lightly spray a 9×11 or 9×9 inch casserole dish with nonstick baking spray, In food processor pulse pretzels, chocolate chips and sugar. Stir in melted butter and press into casserole dish. Place in freezer while you make the mousse,
Combine mousse mix and milk in stand mixer bowl. Blend on low for 30 seconds. Turn mixer to medium and beat for 4 minutes. Spread over pretzel crust and return to freezer.
Place a metal mixing bowl and metal whisk into the freezer for 15 minutes. Place the powdered sugar into the mixing bowl and add the whipping cream. Whisk just until the cream reaches stiff peaks.Carefully spread over the chocolate layer. Try your best not to mix the layers. Sprinkle with chocolate covered pretzels. For ease in cutting refrigerate overnight.