Preheat the oven to 350F.
Begin beating room temperature egg whites in a mixer on a low speed setting.
Once the egg whites become frothy add cream of tartar and continue beating.
Once the cream of tartar is all incorporated, begin adding salt and your sugar alternative in two portions.
Switch your mixer to high until the egg whites become dense and glossy. Add vanilla or preferred flavor extract.
Pipe merengue onto a cookie sheet. Ensure cookies are approximately the same size.
Pop the cookie sheet in the oven quickly without releasing a lot of heat from the oven.
After two minutes, turn the oven off and let the cookies bake as the temperature of the oven gradually decreases. Do not open the oven door to check on the cookies! Patience is key.
Let the cookies sit in the oven until the oven has completely dropped to room temperature. This can take 3 or 4 hours.