1½ tbsp. sugar divided
3 tbsp. unsweetened cocoa powder
4 large egg whites
2 pints mint chip ice cream, softened
½ c. chilled whipping cream
¼ tsp. vanilla
¼ c. chocolate sprinkles
Position 1 rack in top third and 1 rack in bottom third of oven and preheat to 200. Line 2 large baking sheets with parchment paper. Trace two 12 inch rectangles, spaced slightly apart on 1 paper. Trace one 12x4 inch rectangle on second paper. Turn papers over (marked lines should show through). Sift 3 tbsp. sugar, powdered sugar and cocoa into medium bowl. Using electric mixer, beat egg whites in large bowl until frothy. Add 1 1/2 tbsp. sugar and beat until soft peaks form. Gradually add 5 tbsp. sugar beating until whites are stiff and glossy. Fold in cocoa mixture. Spread 1/2 meringue evenly over each marked rectangle. Bake meringues until dry, reversing sheets every hour, about 4 hours total. Turn off oven, leave meringues in oven overnight. Lift meringues from parchment. Place 2 meringues on work surface. Gently spread 1 pint ice cream over each being careful not to press hard to avoid cracking meringues. Place 1 filled meringue, then third meringue, pressing leightly to adhere. Cover and freeze assembled cake at least 2 hours and up to 1 day. Beat cream, vanilla, and remaining 1 tbsp. sugar in small bowl until peaks form. Spread whipped cream on top layer of meringue to cover. Scatter chocolate sprinkles evenly over top.