Let's craft the ice cream cake: Begin by greasing a 3-quart metal bowl. Then, layer it with scoops of sorbet, vanilla ice cream, and half of the chocolate ice cream, alternating between small and large scoops for a visually enticing mosaic. Cover the ice cream with plastic wrap, pressing gently to create a smooth surface. Afterward, remove the wrap, sprinkle wafer crumbs, re-cover, and freeze for approximately 30 minutes.
Begin by unwrapping the ice cream and spreading it evenly on top of the crumbs. Then, slice the pound cake into 1/2-inch-thick pieces, ensuring complete coverage of the ice cream. Use about two-thirds of the cake. Wrap it in fresh plastic and freeze until it's firm, which should take at least 2 hours, but you can also store it this way for up to 2 days.
To make the meringue, whip the egg whites and cream of tartar in a large bowl using a mixer on medium-high speed for approximately 2 minutes. Gradually add the sugar while beating on high speed until the egg whites become glossy and form stiff peaks.
Start by unwrapping the cake and gently inverting it onto a baking sheet lined with parchment paper. If needed, allow it to stand inverted until it releases. Remove the remaining plastic wrap, then generously coat the ice cream with meringue, ensuring the top is slightly thicker than the sides. Use the back of a spoon to create decorative swirly peaks in the meringue. Finally, place it in the freezer for a minimum of 3 hours.