Preheat the oven to 350°F (175°C). Line a 1 x 13 x 9.5 inch jelly roll pan with parchment paper.
Press the refrigerated sugar cookie dough into an even layer across the bottom of the prepared pan.
Bake the cookie layer for 10–12 minutes, or until the edges are golden brown. Remove from oven and cool to room temperature, about 20 minutes.
Let the vanilla ice cream sit at room temperature for about 10 minutes to soften for easy scooping.
In the bowl of a stand mixer (or a large bowl), add the softened vanilla ice cream and the entire 15.6 oz tub of confetti vanilla frosting. Mix until fully combined and smooth.
Spoon the ice cream-frosting mixture over the cooled cookie crust and spread into an even layer. If the frosting contains sprinkles, stir about half of the sprinkles into the mixture and reserve the rest to sprinkle on top.
Smooth the top and sprinkle the remaining sprinkles over the surface. Freeze the pan until the cake is solid, about 1 hour.
Once firm, lift the cake from the pan using the parchment, cut into squares, and serve.