This recipe originally appeared in our Holiday 2021 issue. Get the magazine here.
Preheat the oven to 350°. Spray a large rimmed baking sheet (about 11 by 17 inches) with cooking spray; line it with parchment paper and spray paper. In a large bowl, using an electric mixer on medium, beat the egg whites, cream of tartar, and sea salt until foamy. Gradually beat in the sugar. Increase the speed to high and beat until stiff, glossy peaks form, about 4 minutes. Beat in 1 tsp. vanilla. Sift the cornstarch over the meringue; beat until blended. Using a spatula, fold in the raspberries and chocolate chips.
Scrape mixture onto the prepared baking sheet and spread it evenly to the edges. Bake until puffed and golden but still soft, about 25 minutes. Let cool in the pan on a wire rack (it will collapse as it cools). The meringue can be made 1 day ahead. Cover with plastic wrap or foil and let stand at room temperature.
In a medium bowl, using an electric mixer, beat the heavy cream, mascarpone, 1/4 cup confectioners' sugar, and the remaining 1/2 tsp. vanilla until stiff peaks form.
Place a sheet of foil over the meringue. Place a cutting board on top and invert the meringue onto the board. Spread the jam over the meringue. Spoon dollops of the mascarpone whipped cream on top, then spread out in an even layer. Starting at one long end, roll up the pavlova, using the foil to guide you. Transfer roll to a platter or baking sheet, seam-side down, still wrapped firmly in the foil. Refrigerate for 1 hour. Remove the foil and dust with confectioners' sugar. Slice and serve. (The pavlova can be covered and refrigerated for up to 12 hours ahead.)