Preheat the oven to 300 degrees and line a half sheet pan with a silicone baking mat or parchment paper.

Add the egg whites and cream of tartar to a large bowl. Use an electric mixer with a whisk attachment to beat the egg whites on medium-low speed until soft peaks form.

Once the egg whites can hold a soft peak, slowly add the caster (or granulated) sugar in one tablespoon at a time, continuing to mix the whole time, until all the sugar is added. When the meringue is ready, it should be very thick and stiff.

Divide the meringue into 6-8 mounds on the prepared pan, leaving some space between each mound as they will spread when they bake. (Bake on 2 trays if needed.) Form each mound into a round nest with an indentation in the center.

Bake for 30 minutes. Then turn off the oven and leave the meringues in the oven for 3 hours to dry out and cool slowly. Then remove from oven, cool to room temperature, and store in an airtight container until ready to serve.

To serve, make the whipped cream. Then fill each mini pavlova with the whipped cream and top with fresh berries and garnish with fresh mint.