In a medium pot, whisk together whole eggs, egg yolks, sugar, kosher salt, lemon zest, and fresh lemon juice until smooth. Place the pot over low heat and cook for 3 minutes, then turn to medium-low, stirring continuously for about 8 minutes until the mixture thickens. Strain the curd through a fine sieve to eliminate any lumps, then cover and chill in the refrigerator.

Preheat your oven to 250°F (121°C) and line a baking sheet with parchment paper. In a clean mixing bowl, beat room temperature egg whites and cream of tartar until soft peaks form. Gradually add sugar while continuing to beat until stiff peaks develop, ideally around 7-10 minutes. Gently fold in the white vinegar and cornstarch for added stability.

Transfer the meringue mixture into a piping bag fitted with a round nozzle. Pipe 4-inch circles on the prepared baking sheet, creating a slight indent in the center of each for the lemon curd. Bake in the preheated oven for approximately 45 minutes, until the meringues appear dry and crisp. Turn off the oven and leave the meringues inside to cool for 1-2 hours, which prevents cracking.

Once the meringues have cooled completely, carefully remove them from the parchment paper. Spoon or pipe chilled lemon curd into each meringue nest, filling it generously. For a delightful finish, top with freshly whipped cream, allowing the smoothness to complement the crunchy meringue and tangy lemon curd. Serve your beautiful Mini Lemon Curd Pavlovas immediately for the best texture!