Line a baking sheet with parchment paper. Preheat the oven to 250 F.
Place the egg whites in the bowl of your mixer, along with the cream of tartar. Beat until frothy and foamy. Add half of the the sugar and beat for 30 seconds. Add the remaining sugar, and continue to beat on high until you have very stiff, shiny peaks. You should be able to hold a spoon of the egg whites upside down and they will stay for a minute or so. Beat in the vanilla.
Spoon (or pipe) meringue onto the prepared baking sheet in individual servings about 3-4 inches in diameter. Using the back of the spoon, make an indentation in the center to make a bowl shape. If you are using the pastry bag method, make about three or four layers of swirls to form a shell and then pipe more meringue into the bottom of the shell. See nearby photo.
Bake at 250° F for 30 minutes and then turn oven off and leave them in for another 30 minutes. Don’t open the door! The meringue will become crunchy on the outside, but remain soft on the inside. We also love it when the meringue is crunchy throughout as another option. To make them crunchy all the way through, bake them for 45 minutes before turning off the oven and then leave them in the oven for another 30-45 minutes. Serve right away or store in an airtight container in a cool spot for up to a week or so before using. (If you make one large pavlova, increase baking time by about 10 minutes.)