Place parchment paper over two baking sheets and set aside.
In a stand mixer, beat egg whites, sugar, cornstarch, salt, and vanilla on high for about 10 minutes, until the meringue batter is thick and forms stiff peaks.
Carefully pour meringue batter onto the prepared baking sheets covered with parchment paper into circles approximately 3 inches in diameter.
Bake at 270 degrees Farenheit for 6 minutes, then reduce heat to 220 degrees Farenheit and bake for an additional 1 hour and 10 minutes.
Meanwhile, make the filling.
To Make the Strawberries and Peaches Filling
In a medium bowl, mix together the strawberries, peaches, vanilla, balsamic vinegar. Set aside.
To Make the Whipped Cream
In a mixer, whip heavy cream and sugar together until thick.
Assemble the mini pavlova cakes
Once meringues are done, remove from the oven and allow to cool for a minute or two before assembling. When meringue cookies are done, gently lift from the parchment paper.
Top one meringue cookie with whipped cream, then with a couple of spoonfuls of the strawberry/peach mixture. Top with another meringue cookie and repeat.
Notes
To create even circles, trace the outside of a juice glass onto the parchment paper and then fill the circles with meringue batter.