Separate the cold egg whites from the yolks carefully; any speck of yolk, grease, or residue on the bowl or beaters will keep the meringue from becoming fluffy. Cover the yolks and refrigerate them for another use, then set the whites aside until they reach room temperature, about 30 minutes.

Beat the egg whites and cream of tartar in a deep bowl with an electric mixer on high speed until soft peaks form. Continue beating while adding the sugar one tablespoon at a time, then beat until stiff, glossy peaks form and a little meringue rubbed between your fingers no longer feels gritty. Beat in the vanilla extract.

Heat the oven to 200 degrees Fahrenheit. Line two baking sheets with parchment paper, dabbing a small bit of meringue between the pan and the parchment corners to keep the paper flat.

Scoop the meringue into a large resealable plastic bag and seal it. Snip a 1/2 inch opening across one lower corner and use the bag like a pastry bag to pipe ghost shapes about 2 inches wide and 3 to 4 inches long onto the parchment, leaving about 2 inches between shapes. Gently press two miniature chocolate chips into each ghost for eyes, then repeat with the remaining meringue.

Bake the ghosts until they turn lightly golden, about 1 1/2 hours, rotating and switching the position of the baking sheets halfway through. Turn off the oven and let the meringues rest inside the closed oven for another hour before removing them.