Make the Meringue – Beat the egg whites with vinegar, vanilla, salt, and cream of tartar until foamy. Gradually add sugar, beating until stiff peaks form.
Bake the Meringue – Spoon the meringue onto a parchment-lined baking sheet, forming a nest shape with a slight hollow in the center. Bake at a low temperature until crisp and lightly golden. Let it cool completely.
Prepare the Lemon Curd – In a saucepan, whisk together sugar, potato starch, and water over medium heat until thickened. Slowly add the beaten eggs and lemon juice while stirring continuously. Cook until smooth and stir in the lemon zest.
Assemble the Dessert – Fill the cooled meringue with the lemon curd, smoothing it evenly across the top.
Garnish and Serve – Top with whipped cream and fresh berries for an extra layer of texture and flavor. Serve immediately or refrigerate for later.