Arrange the oven racks toward the center of the oven, spaced evenly apart. Preheat the oven to 300°F. Line two large rimmed baking sheets with parchment paper or silicone baking mats and set aside.
Using a stand mixer or hand mixer, beat the egg whites until they thicken and turn white.
With the mixer running, slowly add the sugar, one or two tablespoons at a time, allowing each addition to fully incorporate before adding more.
Add the cream of tartar and cornstarch. Continue beating until the meringue is stiff, glossy, and holds its shape.
Spoon the meringue onto the prepared baking sheets in equal-sized portions. Use the back of a spoon to create a shallow indent in the center of each pavlova for the toppings.
Place the baking sheets in the preheated oven and bake for 10 minutes.
Reduce the oven temperature to 225°F and continue baking for 45 minutes.
Turn off the oven and let the pavlovas rest inside for 1 hour without opening the oven door.
Remove the pavlovas from the oven. Top with whipped cream, fresh berries, mini chocolate chips, and fresh herbs, if using.
Serve immediately after topping.