Using an electric mixer, beat the egg whites, cream of tartar and vanilla until foamy. Gradually add the sugar and continue beating until stiff. Meringue should hold a shape well. Mix half of the meringue with green food color (I usually add a drop or two of yellow too). Top two baking sheets with parchment.
For upright green trees, insert a medium star tip into a piping bag, then fill with green meringue Pipe out tree shapes on to the parchment, starting with a larger circle then going smaller and smaller, ending with a point. Sprinkle with gold stars or dot with candy cane sprinkles (or decorate with other sprinkles of your choosing).
For the white flat trees insert a small star tip into a piping bag, then fill with white meringue Pipe out tree shapes on to the parchment, starting at the top, then going back and forth drawing longer and longer lines until the trree’s the size you want. Sprinkle with gold stars (or decorate with other sprinkles of your choosing)
Bake for 45 minutes, then turn the oven off and let sit in the closed oven (no peeking) another 45 minutes if possible.
I am not a health professional and nutrition data is calculated programatically. Accuracy may vary with product selection, calculator accuracy, etc. Consult a professional for the best information.