1Scrape off and discard the frosting from the cupcakes; crumble cupcakes into crumbs. Press all but 1/4 cup crumbs into bottom and up sides of a 9-inch deep-dish plate. Freeze for 30 minutes.
2Meanwhile, let the ice cream and sorbet soften at room temperature, about 15 minutes. Spread the ice cream evenly over the crust; spread the sorbet on top of ice cream. (return pie to freezer between layers if ice cream gets too soft). Freeze pie again while you make the whipped cream.
3Beat the heavy cream and powdered sugar in a large bowl with mixer on medium-high speed until soft peaks form, about 3 minutes. Top pie with whipped cream, and sprinkle reserved cupcake crumbs around edges.
4Freeze pie until firm, at least 4 hours or overnight.