Preheat the oven to 200 degrees and line a baking sheet with parchment paper.

Place the egg whites and cream of tartar in a clean mixing bowl. Beat on medium speed until soft peaks form.

Add the sugar a little at a time while beating on high speed. Continue until the mixture reaches stiff, glossy peaks.

Mix in the vanilla extract on low speed until just combined.

Spoon the meringue into a piping bag fitted with a round tip. Pipe ghost shapes onto the prepared baking sheet, leaving space between each one.

Press two mini chocolate chips into the top of each ghost to form eyes.

Bake for 2 hours until the cookies feel dry and lift easily from the parchment. Turn off the oven and let them cool inside with the door closed for 1 hour.