How to Make It
Prepare the Meringues: Preheat oven to 225°F. Trace 2 9-inch circles on a sheet of parchment paper. Place parchment, pencil-side down, on a baking sheet. Whisk together sugar, cornstarch, cream of tartar, and salt in a bowl. Beat egg whites on high speed with an electric mixer until soft peaks form. Gradually add sugar mixture, 2 to 3 tablespoons at a time, beating to incorporate after each addition. Beat on high until stiff peaks form; beat in vanilla. Divide meringue between 2 circles on parchment, spreading to cover circles. Bake in preheated oven until slightly puffed, 1½ hours. Turn oven off and let meringue stand in oven until dry, 8 hours or overnight.
Prepare the Roasted Apples: Preheat broiler with oven rack 6 inches from heat. Toss apples with butter, sugar, and cinnamon; toss to coat. Arrange apple slices in a single layer on a baking sheet coated with cooking spray. Broil 5 minutes; stir slices. Broil until tender and golden, about 5 minutes. Cool completely.
Prepare the Pumpkin Cream: Stir together pumpkin, sugar, pumpkin pie spice, and salt in a medium bowl. Beat cream on medium-high speed until frothy. Gradually add powdered sugar to whipped cream, beating until stiff peaks form. Stir about one-third of the sweetened whipped cream into pumpkin mixture. Gently fold in remaining sweetened whipped cream. Chill until ready to use.
Place meringue on a serving plate. Top with half of the pumpkin cream, leaving a ½-inch border. Arrange half of roasted apples on pumpkin cream. Top with second meringue. Top with remaining pumpkin cream, spreading to the edge. Top with remaining apples.
Note: Active Time includes 8 hours standing