Prepare the Lemon Curd: In a medium pot, whisk together whole eggs, egg yolks, sugar, kosher salt, lemon zest, and lemon juice. Cook over low heat for 3 minutes, then switch to medium-low, stirring continuously until the mixture thickens and reaches 170°F (about 8 minutes). Strain into a bowl and let it cool; refrigerate if you'd like to chill it further.

Make the Meringue Shells: Preheat your oven to 250°F and line a baking sheet with parchment paper, drawing 4-inch circles for guidance. In a stand mixer, beat egg whites and cream of tartar until soft peaks form. Gradually add sugar until stiff peaks form. Gently fold in vinegar and cornstarch.

Pipe Meringue Nests: Using a piping bag, carefully pipe the meringue mixture into the drawn circles, creating sweet little nests. Bake for 45 minutes until the meringues are dry and crisp. Once done, turn off the oven and let them cool inside for 1-2 hours.

Assemble the Pavlovas: Gently fill each meringue nest with a spoonful of your luscious lemon curd, then top it off with a generous dollop of whipped cream. Serve immediately to enjoy the contrast of textures!