Preheat the oven to 275 degrees Fahrenheit.
In a large bowl, whisk egg whites on a medium speed until frothy.
Add in salt and cream of tartar on full speed until stiff peaks are formed.
Whisk in sugar and cornstarch in small batches until everything is fully incorporated and the meringue has become stiff and glossy.
Split the meringue into 6 even batches. Whisk in flavorings and food coloring into each batch. I did red (cherry), orange (peach), yellow (mango), green (green apple), blue (blueberry), purple (blackberry),and white (vanilla) for color and flavor combinations.
Put each batch into an individual piping bag and pipe the meringue onto a baking sheet line with parchment paper in a rainbow shape (see above in the post for images). This does not use the white meringue.
Pipe the white meringue into two cloud shapes, gently make a bowl in the center of each cloud.
Bake for 1 ½ hours of until the outside is crispy. If the meringue starts browning, turn down the over for the remaining time. Allow the meringue to cool in the oven with the door closed to help prevent cracking.