If you have a milk frother, pour all the ingredients into a large mug and insert the whisk end of the frother into it. Turn it on and allow it to froth the mixture until silky, smooth, and velvety in texture, about 5 minutes.
To make it without a frother, empty all the ingredients into a blender and blend at high speed until silky, smooth, and velvety in texture, about 1 minute.