Using a 4-inch tart ring, round cutter or bowl, trace 6 circles on the parchment paper. Transfer the parchment paper to a baking sheet tracing-side down.
Preheat the oven to 325°F.
For the meringue, place egg whites in a bowl of a stand mixer (or a heatproof bowl) set over a saucepan of gently simmering water to make a double boiler making sure the water does not touch the bottom.
Using a large balloon whisk, gradually whisk in the sugar. Whisking constantly, heat the egg and sugar mixture until it reads 170°F on a candy thermometer and the mixture starts to froth and sugar dissolves.
Transfer the bowl to the stand mixer fitted with the whisk attachment. Whisk the mix on high speed for about 5 minutes until stiff peaks form.
Turn the mixer to low, add in the vinegar and corn starch, then whisk on high speed for another minute until well combined.
Place a smidge of the meringue in each corner of the baking sheet to stick down the parchment paper so that it does not move when you are piping the pavlova.
Transfer the meringue to a piping bag attached with the French star tip size 869.
Pipe the meringue along the circumference of the drawn circles.
Place the baking sheet in the oven and immediately reduce the temperature to 225°F. Bake the pavlova nests for 40 minutes. When the pavlova nests are done baking, without opening the oven door, turn off the oven and allow the them to cool in the oven for a minimum of two hours or overnight.