Step 1: Preheat your oven to 200°F (95°C) and line two large baking sheets with parchment paper.
Step 2: In a completely clean glass or metal bowl, beat the egg whites and cream of tartar on medium-low speed until foamy.
Step 3: Increase the speed to medium-high and add the superfine sugar one tablespoon at a time, ensuring it is well incorporated before adding more.
Step 4: Continue beating until stiff, glossy peaks form and the mixture is no longer grainy when rubbed between your fingers; add vanilla extract at the very end.
Step 5: Transfer the mixture to a piping bag and pipe ghost shapes onto the prepared baking sheets.
Step 6: Bake for 90 minutes, then turn off the oven and let the meringues cool completely inside with the door slightly cracked.
Step 7: Once cool, use melted chocolate to paint eyes and mouths onto your ghosts.