• Position rack in the middle of the oven and preheat to 275ºF. Lightly butter three (8-inch) round cake pans and dust with confectioners' sugar, knocking out the excess. Line the bottom of the pans with rounds of parchment paper.

For the Meringues

• In the bowl of a food processor, pulse the superfine sugar, brown sugar, and cornstarch until well combined; set aside. In a small bowl, combine the vanilla and vinegar; set aside.
• In the bowl of a stand mixer fitted with the whisk attachment, beat egg whites with a pinch of salt at medium speed until they hold soft peaks. Increase speed to medium-high and add the sugar mixture one tablespoon at a time. After all the sugar is incorporated, continue to beat for one minute more. Add the vinegar mixture, then beat at high speed until meringue is glossy and holds stiff peaks, about 5 minutes. Spoon the meringue into the prepared pans (about 2 ½ cups or 173 grams per pan) and smooth the tops using an offset spatula.
• Bake until the meringues have a crisp crust and feel dry to the touch, about 1 hour (insides should be moist and marshmallow-like). Turn the oven off and prop the door open slightly with a wooden spoon. Cool the meringues completely in the oven. (They will slightly collapse and crack.)
• Run a knife along the insides of the pans and carefully turn out the meringues and remove parchment paper. (Meringues will be fragile and may crack further). Carefully turn meringues right side up; set aside until ready to assemble.

For the Berries

• Toss the berries with the sugar and let stand at room temperature for up to an hour.

For the Cream

• In a large chilled bowl, beat together the heavy cream, crème fraîche, sugar and vanilla using a wire whisk or an electric mixer until it just holds soft peaks.

To Assemble

• Place one meringue on a serving platter and spread with ⅓ of the whipped cream. Spoon ⅓ of the berry mixture with juice on top of cream. Repeat layering with remaining meringues and fruit. Serve immediately. Enjoy!