01 - Preheat oven to 200°F. Line two baking sheets with parchment paper.
02 - In a clean, dry mixing bowl, beat egg whites and cream of tartar on medium speed until soft peaks form.
03 - Gradually add granulated sugar, 1 tablespoon at a time, beating on high until stiff, glossy peaks form and sugar dissolves. Continue for 5 to 7 minutes.
04 - Beat in vanilla extract until just combined.
05 - Spoon the meringue into a piping bag fitted with a large round tip or use a zip-top bag with the corner snipped. Pipe 2-inch tall ghost shapes onto the prepared baking sheets, leaving about 1 inch between each.
06 - Lightly press two mini chocolate chips into each ghost for eyes. If using melted chocolate, bake first and apply eyes after cooling.
07 - Bake meringues for 1 hour 30 minutes, or until dry to the touch and easily removed from the parchment.
08 - Turn off the oven, crack the door, and let meringues cool completely inside to prevent cracks.
09 - If using melted chocolate, use a toothpick or a small piping bag to dot eyes onto cooled meringues.