Make the Pavlova: Preheat the oven to 250 degrees F. Line a baking sheet with parchment paper and draw a 9-inch circle in the middle (I traced 8-inch parchment rounds, but you could cake pans or anything else about the same diameter). Spray lightly with non-stick cooking spray.
Using an electric mixer with the whisk attachment, beat the egg whites on medium speed until frothy, then add the cream of tartar. Increase the mixer speed to medium-high and beat to soft peaks. While continuing to beat the egg whites, gradually add the granulated sugar (I estimate that I added about 3 tablespoons at a time) and beat until glossy and stiff peaks form. Spoon the mixture onto the circle, and use a spatula to shape the egg white mixture into a circle with decorative sides, if desired.
Bake for 1 hour, or until firm to the touch.Turn off the oven and prop the oven door open with a wooden spoon. Allow the pavlova to cool completely in the oven.
Make the Whipped Cream: Place the heavy cream, sugar, and vanilla extract in a large bowl and beat on medium-high speed until it holds stiff peaks.
Transfer the pavlova to a serving platter, then top with the whipped cream and fresh fruit. Serve immediately or refrigerate for up to 4 hours.