Step 1: Preheat your oven to 250°F (120°C) and line a baking sheet with parchment paper. Draw a 9-inch circle on the parchment as a guide, then flip the paper over.
Step 2: In a clean, grease-free bowl, whisk the egg whites until soft peaks form. Gradually add the caster sugar one tablespoon at a time, whisking constantly until the mixture is thick, glossy, and the sugar has completely dissolved.
Step 3: Gently fold in the white vinegar and cornstarch using a spatula, being careful not to deflate the meringue.
Step 4: Pile the meringue onto the prepared parchment paper within the circle. Use a spatula to level the top and create a slight well in the center, smoothing the sides upward.
Step 5: Reduce the oven temperature to 200°F (100°C) and bake for 90 minutes. Once finished, turn off the oven and leave the pavlova inside with the door slightly ajar until completely cool.
Step 6: Just before serving, whip the heavy cream until soft peaks form. Spread the cream into the center of the pavlova, swirl in the citrus curd, and top with the prepared citrus segments, zest, and mint.