Pavlova with Mixed Berries

Cut a circle of parchment paper about the size of the dish you intend to serve the pavlova on — about 9 inches is good. Using a large, completely clean, dry bowl and an electric mixer with whisk attachment (or by hand with a whisk), beat egg whites on low/medium at first, then once they start to foam, move up to medium to medium-high speed. Beat until soft peaks form and the whites have tripled in volume. Continue beating on medium speed while very slowly adding the 1¼ cups sugar, taking about 10 minutes to fully incorporate. Beat until thick and glossy. On the lowest speed, slowly incorporate 1 teaspoon vanilla extract, vinegar, and cornstarch.

Preheat oven to 300 F. Place parchment paper on a cookie sheet and spoon mixture inside the circle. Working from the center, spread mixture outward, building the edge up a bit and leaving a slight depression in the center, keeping about an inch away from the edge of the circle. Bake for 1 hour (avoid opening the oven during this time), then turn oven off and leave pavlova in there to cool completely, 2 to 3 hours.

When ready to serve, remove from parchment paper and place pavlova on a flat serving platter. Beat heavy cream, remaining tablespoon sugar, and remaining teaspoon vanilla on medium-high until stiff peaks hold their shape without wilting. (Overbeating will turn the cream into butter!) Fill the center of pavlova with whipped cream and cascade berries across the top and around the sides. To serve, cut into wedges and eat immediately.