Heat oven to 300°. Line baking sheet with parchment paper.
In a large bowl add egg whites and beat with an electric hand mix until egg whites are stiff. Gradually add in sugar, a tablespoon at a time, beating sugar into eggs after each tablespoon of sugar addition.
Continue to beat egg mixture until very thick and glossy. Add vanilla, lemon juice and cornstarch. Beat until well combines.
Add mixture to a pastry bag and pipe into 8 circle size discs on parchment paper.
Bake for 30 minutes and then turn heat off but leave pavlova in oven for an additional 30 minutes with with oven door closed.
Finish cooling on a wire rack.
Top pavlova with Cool Whip and mixed berries.
Hint: Pavlova are best eaten the same day. Don’t refrigerate the pavlova because they’ll lose their crispness. You can store the leftover in an airtight container for 2-3 days, and top with whipped cream and berries just before serving.