Preheat oven to 350°F (176°C). Line a baking sheet with parchment.

In the bowl of a stand mixer, using the whisk attachment, whisk the egg whites and cream of tartar on medium speed (speed 4 for KitchenAids) until a soft peak forms, about 5 minutes

Turn the speed to low (speed 2) and slowly add the sugar, 1-2 Tablespoons at a time. Allow it to fully incorporate in between each addition, about 30 seconds. This may take a total of 5-7 minutes. Once the sugar has been added, increase speed to medium-high (speed 6). Beat mixture until glossy stiff peaks form, about 2 minutes. You should be able to turn the whisk upside down and the meringue mixture won't move. 

Add the vanilla extract and beat for one more minute.

Fold in the vinegar with a rubber spatula. 

Sprinkle the cornstarch over the mixture and fold it in. You can dip your spatula in the mixture and slightly shake it to disperse the cornstarch, making it easier to incorporate. Mix on high speed for 15 seconds for one last whip to incorporate these ingredient additions.

Spread mixture into an 8-inch circle in the center of the parchment. Make a slight well in the center where your toppings will go later. 

Place in the oven on the middle rack of the oven. Turn oven down to 225°F. Bake for 90 minutes, until the Pavlova is dry and firm. The Pavlova should have a very light off-white color when done. Do not open the door as the change in air temperature can cause the Pavlova to crack. 

Turn the oven off, leave the door closed. Turn on the oven light. Let the Pavlova cool in the oven for at least three hours before serving. You can also store it in the oven with the light on for up to 24 hours. However, it is best served same day. 

To serve, top it with whipped cream, Lemon Curd and your favorite berries. Slice and enjoy! 

See notes for serving and storage suggestions.