Preheat the Oven: Start by preheating your oven to 350°F (175°C). Line a 12-cup muffin pan with cupcake liners.

Mix the Dry Ingredients: In a large mixing bowl, combine the flour, sugar, cocoa powder, baking soda, and salt. Stir everything together until evenly mixed.

Add the Wet Ingredients: Add the water, vegetable oil, vinegar, and vanilla extract to the dry ingredients. Stir until just combined and no streaks of flour remain. Be careful not to overmix.

Fill the Cupcake Liners: Divide the batter evenly among the cupcake liners, filling each about two-thirds full.

Bake: Place the muffin pan in the preheated oven and bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool in the pan for about 10 minutes, then transfer them to a wire rack to cool completely.

Prepare the Frosting: While the cupcakes are cooling, make the ghost frosting. In a heatproof bowl over a pot of simmering water, combine the egg whites, sugar, and cream of tartar. Whisk continuously until the mixture reaches 160°F (70°C) on a candy thermometer.

Whip the Frosting: Transfer the mixture to a stand mixer with the whisk attachment. Beat on high speed until stiff peaks form and the frosting is glossy, about 5-7 minutes. Add the vanilla extract and beat until just combined.

Pipe the Ghosts: Transfer the frosting to a piping bag fitted with a large round tip. Pipe generous mounds of frosting onto each cupcake, creating a ghost shape. Use mini chocolate chips to create eyes and mouths on each ghost.

Serve and Enjoy: Your Halloween Ghost Cupcakes are ready to enjoy! Serve them at your Halloween party or share them with family and friends.