Making a frothy batch of milk in the microwave is only a 2-step
process. All that is needed is some 2% or nonfat milk poured into your
jar, you then simply shake your sealed jar with the milk inside so that
it starts to bubble and foam-up.
Once you have given it a good shake place the jar directly into the microwave and blast away for a few seconds. By using the microwave you’re helping to stabilize the foam (if you didn’t use a microwave the foam would simply disperse and collapse)