Place the egg whites, sugar, and cream of tarter in a large bowl.

Bring 2-inches of water in a saucepan to a simmer, then place the bowl on top of the saucepan. Do not let the bowl touch the water.

Whisk egg white mixture constantly for 3-4 minutes, or until thin, smooth, and sugar has completely dissolved. If you have a kitchen thermometer, check that the temperature has reached 160° Fahrenheit.

Remove bowl from saucepan, add in vanilla extract, then while still hot beat with a hand or stand mixer until super light and fluffy, about 5 minutes. Serve marshmallow dip alongside fresh fruit.