Preheat oven to 200°F and line two baking sheets with parchment paper.
Whisk egg whites and cream of tartar on low speed until foamy, then turn mixer to high speed.
6 large egg whites, 3/4 tsp cream of tartar
Add sugar one tablespoon at a time, mixing in between. Once all the sugar is added continue mixing on high speed until it is thick and shiny.
1 3/4 cups + 2 TBS granulated sugar
Once meringue forms stiff peaks and all sugar is completely dissolved it's ready. To double check, rub a small amount of the meringue between your fingers. It should feel smooth, not gritty. If needed, continue mixing until smooth.
Stir in the flavored extract and food coloring and stir until well mixed and color is even throughout.
1 tsp vanilla extract, holiday sprinkles, green gel food coloring
To make pops, dip the lollipop stick about 1/2 way into the meringue mixture then put on baking sheet, leaving enough space between each stick to pipe your Christmas Tree shape. If making cookies, skip this step.
Transfer the meringue into a large piping bag with a large tip. Round, star or flat tips work best.
For pops, pipe the meringue onto the dipped end of the sticks in a Christmas tree shape starting near the middle of the stick with longer lines and making the lines shorter as you get near the top. If making cookies, do the same thing directly onto the parchment paper, making sure to fill in tree shape completely. Add sprinkles, if desired.
Bake for 1 hour, then turn off the oven but do not open the door. Let cookies cool completely in the oven for 1-2 hours. Meringue should be dry, crisp and very airy when done.
Notes
Use a kitchen scale to make sure that your sugar is twice the amount in grams as your egg whites for proper whipping.Super-fine granulated or caster sugar work best in this recipe. Regular granulated will work though, but not powdered sugar.Bowl must be completely grease-free or the meringue may not whip up.Make sure there is no egg yolk in your whites as this can also prevent them from whipping properly.Store cooked meringue in an airtight container in a dry area for up to 2 weeks.Do not refrigerate or freeze.