Measure out 1 cup of milk.
Mix 2 tablespoons sugar, 4 teaspoons unsweetened cocoa powder , and 2 tablespoons of the milk in a mug until smooth.
Heat the remaining milk in a small saucepan on the stovetop or in a 2-cup glass measure in the microwave until steaming hot but not boiling.
Stir in the cocoa mixture and 1/4 teaspoon vanilla extract.
