1. Fill a medium saucepan 1/4 full with water. Set the saucepan over medium heat, and bring water to a simmer.

2. Combine egg whites, sugar, and cream of tartar in the heatproof bowl of electric mixer; place over saucepan. Whisk constantly until sugar is dissolved and whites are warm to the touch, 3 to 4 minutes. Test by rubbing between your fingers; egg whites should feel smooth.

3. Transfer bowl to an electric mixer fitted with whisk attachment, and beat, starting on low speed, gradually increasing to high until stiff, glossy peaks form, 5 to 7 minutes. Add vanilla, and mix until combined.

4. In the same bowl, add black food coloring, one drop at a time. Beat with the whisk attachment until color is incorporated. Continue adding drops and beating until meringue reaches deep black color. Be sure to use meringue immediately.