Instructions

In a small bowl, lightly beat egg whites and set aside. In a large bowl,
combine cocoa and cornstarch. Whisk 3/4 cup of milk into cocoa mixture
until completely smooth.
In a large heavy saucepan, combine remaining milk, sugar, and salt. Mix
well. Bring to a boil over high heat, whisking constantly. Remove pan
from heat.
Whisk cocoa mixture into hot milk mixture. Bring to a boil over
medium-high heat; boil for 2 minutes, whisking constantly. Remove pan
from heat.
Gradually whisk 1 cup of hot cocoa mixture into the egg whites. Pour