How to Make It
Preheat the oven to 200°. Line a baking sheet with parchment paper. In a small bowl, stir the vinegar with the cornstarch to form a slurry.
In the bowl of a stand mixer fitted with the whisk, beat the egg whites at medium speed until soft, frothy peaks form. Increase the speed to medium-high and gradually add 1/3 cup of the sugar; beat for 2 minutes. Repeat with the remaining sugar in 2 batches, beating for 2 minutes between additions. Continue to beat until the meringue is stiff and glossy, 7 to 8 minutes. Sprinkle the slurry over the meringue and fold it in.
Using a large spoon, dollop the meringue onto the prepared baking sheet. Using an offset spatula, spread the meringue 1 1/2 inches thick. Bake for about 3 hours, until firm and white; turn off the oven and keep the oven door slightly ajar. Leave the meringue in the oven for 2 hours, until mostly dry but still slightly chewy.
In a glass bowl, combine the egg yolks, lemon juice and sugar and whisk until smooth. Place the bowl over a saucepan of simmering water (do not let the bottom of the bowl touch the water) and cook, whisking constantly, until the curd has thickened to the consistency of cake batter, about 20 minutes. Remove the bowl from the heat and whisk in the butter, a few cubes at a time, until incorporated. Press plastic wrap directly onto the surface of the lemon curd and let cool to room temperature. Refrigerate for 1 hour, or until cold.
In a large bowl, combine the cream, sugar and vanilla and beat with an electric handheld mixer until soft peaks form. Refrigerate.
To serve, break the meringue into small pieces. Spoon half of the meringue and 1/4 cup of lemon curd into each of 8 parfait glasses. Top with 1/2 cup of whipped cream and a few raspberries. Repeat with the remaining meringue, lemon curd, whipped cream and raspberries. Serve immediately.