It is easiest to separate eggs when they are cold, so carefully separate your eggs straight out of the fridge. Then cover your bowl with the egg whites and leave on the counter until they are room temperature, about a half hour.
Preheat oven to 200°F and place a sheet of parchment paper on a cookie sheet.
Beat your egg whites and cream of tartar on medium until they begin to froth. While still mixing, slowly add sugar and cornstarch until completely incorporated.
Turn mixer up to high and beat until you have stiff peaks, about 5 minutes.
Spoon into a pastry bag with a large round tip (I used tip 2A) Pipe into swirls on the parchment lined cookie sheet.
Place in oven and bake until dry, about an hour and a half. Add a little extra time if it is a humid day. Remove from oven and cool completely.
Using a toothpick and black food gel, gently add faces to your ghosts and allow to dry.