Preheat the oven to 250°F. Add the lemon curd ingredients to a saucepan over medium heat and stir until a thick, smooth cream forms. Let it cool down before moving onto the next step.
For the pavlova, add the sieved sugar and corn starch to the egg whites, together with the salt, and mix together. Add the vanilla extract and white vinegar, and continue mixing until the cream is shiny.
Line a sheet pan with parchment paper and place a springform ring (without the base) on the pan. Fill the ring with the pavlova cream and then carefully remove the ring. Slide the tray into the oven and bake for 2 hours and 20 minutes.
Let the pavlova cool down before garnishing with powdered sugar, lemon slices, blueberries, and a mint leaf.