Preheat and prepare
Preheat your oven to 200°F (about 90°C). Line your baking tray with parchment paper to avoid sticking and promote even baking.

Beat the egg whites
In a clean, dry mixing bowl, pour in the 4 room‑temperature egg whites. Using an electric mixer on medium speed, begin beating until the whites become foamy.

Stabilize with cream of tartar
Sprinkle in the ¼ teaspoon of cream of tartar. Continue beating until soft peaks form — the mixture should hold shape loosely when you lift the beaters.

Incorporate sugar gradually
Increase the mixer speed to high. Add the sugar slowly — a spoonful at a time — allowing it to dissolve thoroughly before adding the next. This gradual addition helps to create a smooth, glossy meringue that holds stiff peaks.

Add vanilla
Once the meringue forms stiff, glossy peaks, gently fold in the ½ teaspoon of pure vanilla extract for aroma and depth of flavor.

Pipe the meringue trees
Transfer your meringue mixture into a piping bag fitted with a star or round tip. On the prepared baking sheet, pipe small tree shapes — start with a wide base and taper to the top, forming a triangle. For a layered, branch‑like effect, pipe in concentric rings that get smaller toward the top. Leave enough space between each tree so air can circulate as they bake.

Bake slowly
Place the baking sheet in the preheated oven. Bake for 1.5 to 2 hours, or until the meringues are completely dry and crisp to the touch.

Cool gradually
After baking, turn off the oven but leave the meringues inside to cool for another hour. This slow cooling helps them dry out completely, ensuring crispness rather than chewiness.

Assemble the cookies
Once cooled, take a sugar cookie base and gently place a meringue tree on top. If desired, use a small dab of icing or melted chocolate to help the tree stick securely.

Decorate
Finish with festive sprinkles, edible glitter, or mini candies for decoration — green sprinkles for a traditional look, or bright colors to match your holiday theme.