1. Preheat oven to 250 degrees. Using a pencil, trace** a 8-9″-diameter circle (use a pie or cake pan to trace around) on a piece of parchment paper. Place on a rimmed baking sheet, pencil-side down.
2. Rub the cut side of the lemon (after zesting then juicing!) around the inside of your mixing bowl, this removes any residual fat on the sides of the bowl*.
3. Gently combine the sugar and cornstarch.
4. Whisk egg whites and pinch of fine sea salt on medium speed until it is bubbly and increasing in volume. Keeping the mixer at medium to medium-high ensures enough time for the sugar to dissolve, having the mixer too high, grainy sugar.
5. Gradually, add one tablespoon at a time, of the sugar mixture, beating until stiff and glossy peaks form. You should not be able to rub the meringue between your fingers and feel any sugar grains. Beat in lemon zest, lemon juice, and vanilla.
6. Plop the mixture into the center of the circle on the parchment. Then using the penciled circle as a guide, with an offset spatula, form the meringue into a mound. Make sort of a well in the center (which will hold the cream and berries) of the meringue.
7. Bake for about 1 hour to an hour and fifteen minutes. Turn off heat; leave in the oven with it ajar (use a wooden spoon to hold it open) until completely cooled (this helps prevent cracking***).
8. Once completely cooled, using two large spatulas, transfer to a cake stand or serving plate.
9. To serve, whisk the Greek yogurt with heavy cream with 1 tablespoon honey (if using) until silky and holds a soft peak; mound in the middle of the pavlova.
10. Tumble on the berries and serve.

Use a glass or stainless steel bowl, not plastic, which can have oil (no matter how much you scrub). The whites won’t whip if there is any oil in the bowl, on the whisk or spatula.