In the microwave or on the stove top, boil Ready-Set-Serve Orange Juice and water. Measure out the evaporated milk, cane sugar, and cocoa powder in a heat proof bowl or mug. When the orange juice and water mixture has come to a boil, pour it into the evaporated milk mixture while continuously whisking to prevent the evaporated milk from curdling. Keep whisking for about one minute until all ingredients are incorporated. Garnish with additional cocoa powder, if desired.