Preheat your oven to a gentle 200°F (about 93°C). Line a baking sheet with parchment paper to prevent sticking.
In a large, perfectly clean and dry mixing bowl, combine the egg whites, cream of tartar, and a pinch of salt. Beat with an electric mixer on medium speed until the mixture becomes wonderfully foamy. Remember, a clean, dry bowl is essential for super fluffy meringues!
Gradually sprinkle in the powdered sugar-free sweetener while continuing to beat the mixture. If you're adding any festive food coloring or flavor extracts, mix them in now. Keep beating for about 3-5 minutes until the meringue forms very stiff, glossy peaks. You should be able to hold the bowl upside down without anything moving!
Carefully spoon your stiff meringue into a piping bag fitted with your favorite tip (a star tip makes beautiful, festive shapes!). Pipe small, bite-sized cookies onto your prepared baking sheet, leaving about 1/2 inch between each one.
Bake in your preheated oven for 1 hour. After baking, turn off the oven, but do not open the door! Let the meringue cookies stay inside the cooling oven, undisturbed, for another hour. This slow cooling process helps them become perfectly crisp and dry all the way through.
Once completely cooled, transfer your healthy, sugar-free meringue cookies to an airtight container. They're perfect for guilt-free holiday snacking or sharing!