Add the room temperature egg whites to a clean bowl of your stand mixer or a large bowl if you are using an electric hand mixer. Whisk on medium speed for about 3-5 minutes or until your eggwhites become frothy.
½ cup egg whites
With the mixer on, stream in the granulated sugar and once incorporated add in the flavoring. If you are using peppermint extract, I would use about ¾ teaspoon.
¾ cup granulated sugar, 1 teaspoon peppermint bakery emulsion
Increase the speed of the mixer to high and whisk until stiff peaks form. This means that when you lift the whisk attachment the egg whites stand up and don't droop over.
Adding Color to the Meringue
Stick a toothpick into the red (or whatever color you want) gel food coloring and make strokes through the meringue after it has formed stiff peaks. Do not mix the meringue unless you want solid color meringues. I usually dip the toothpick into the gel food coloring 6-8 times. Fill the piping bag with the meringue (do not mix the food coloring in unless you want solid color meringues) and pipe swirls onto prepared trays. This swirl of color is only going to work with a piping bag.
Making the Cookies
Line your baking trays or dehydration racks with parchment paper. Fill a pastry bag with the meringue and using a large closed star piping tip, pipe swirls about 2-3" in diameter and 1" in height. Or simply scoop out about 1 Tablespoon of the meringue on to the parchment and make little swirls in the top with a fork.
Dehydrator Instructions
Place the trays with the meringue cookies into the dehydrator and set the temperature to 175℉/80℃ and set the time for 4 hours. When the time is up, leave the cookies in the dehydrator for 4-8 hours.
Oven Instructions
Preheat the oven to 200℉/90℃. Place the trays of merinuges on the center rack or as close to the middle of the oven as you can. Bake for 90 minutes and turn the oven off. Leave the meringues in the oven for at least 4 hours, but overnight is better.
Storage
Once the meringues have sat in the dehydrator or oven and are completely cool, place them in a freezer bag and sqeeze as much air out as possible. Store at room temperature. They have stayed fresh for me at room temp for a month. I recommend freezing them for longer storage.
The amount of cookies you get from one batch will depend on how big you make them, but I average around 40 cookies per batch. For specific Ninja Foodi instructions see the main article or watch the video. Tips for Making Meringue Cookies
Don't make them on a humid day. Humidity can prevent them from drying enough and they may end up chewy and sticky.
Make sure the mixing bowl and all utensils are clean and dry and free from any oil residue. Oil/fat prevents the egg whites from whipping up.
Line the sheet pan or dehydrator tray with parchment or the cookies will stick
Make them in the evening so they can sit in the oven or dehydrator overnight to finish drying.
Store the cooled meringue cookies in plastic freezer bags at room temp for 2-3 days and in the freezer for longer storage.