Adjust oven rack to the medium position; heat oven to 200°F. Line a baking sheet with parchment paper.
Whip egg whites, vanilla and cream of tartar in a large bowl at medium-low speed until foamy (about 1 minute). Increase speed to medium high and whip until soft peaks form (about 1 minute). Gradually add the sugar and continue whipping until stiff peaks form (2-3 minutes).
Scoop 6 mounds of meringue onto the baking sheet. Using a spoon, form each mound into a bowl shape. Bake meringues until they look dry, about 2 hours. Turn off oven but keep the sheet in the oven until the meringues are completely hard, about 2 more hours. If not using right away, seal in an airtight container or bag and store at room temperature for up to 2 weeks.
For the berries
Toss berries with sugar in a medium bowl. Let sit until juicy, about 10 minutes.
For the whipped cream
Whip cream, vanilla and sugar in a large bowl on medium high speed until soft peaks form.
Spoon about ¼ cup whipped cream onto each meringue. Top with berries and serve.
Any combination of fresh fruit can be used in place of the berries. Taste the fruit before adding the sugar to determine if more or less sugar is required.