Preheat your oven to 275 degrees Fahrenheit and line a baking sheet with parchment paper.
Turn the parchment paper over and trace 6-8 small circles with a dark permanent marker, spaced evenly and apart from one another. Turn the parchment paper back over again so you can see the circles through the paper, but the ink won't transfer to the meringues. Set aside.
In a large bowl with a hand mixer, or in the bowl of your stand mixer, whip the room temperature egg whites on medium speed until foamy (about 2-3 minutes).
Once foamy, add the cream of tartar and continue whipping on medium high speed.
Add the sugar slowly in a steady stream while the egg whites continue whipping and begin to turn white and glossy. Adding the sugar slowly ensures that the egg white mixture stays fluffy and light (dumping the sugar in all at one would crush the air out of the egg white mixture).
Whip on high speed until the mixture reaches stiff peaks. You'll know the peaks are stiff when you remove the beater attachment, turn it upside down, and the meringue mixture stands almost straight up.
Add the meringue mixture to a piping bag with a large round opening.
Pipe the meringues onto the prepared baking sheet starting in the middle of the circle and piping around until you reach the outside of the circle. Then pipe one more layer just around the outside of the circle, to create the "nest" effect.
Bake at 275 degrees Fahrenheit for about 45 to 50 minutes, or until the meringues appear dry on the outside and inside of the nests, but haven't browned at all on the bottom or sides.
Let the meringues cool completely to room temperature on the baking sheets.
In the meantime, whip the whipping cream and add the sugar as it whips to soft by slightly stiff peaks.
Scrape the seeds from the vanilla bean and add them into the cream as it whips.
Dollop a portion of the cream into each of the meringue nests after they have cooled completely.
Top with the fresh berries and serve immediately.
To make ahead of time, prepare the meringues and store under a light kitchen towel for up to 18 hours ahead of serving. Assemble with whipped cream and fruit directly before serving.