In a small bowl, make a paste out of 1 tablespoon of heavy cream, the espresso, and the cocoa powder. Add the paste and the remaining ingredients to your blender. Blend for 20 seconds. Pour into a bottle and refrigerate until ready to serve.
Instant coffee can be used in place of the instant espresso. Mason jars are great for storing if you don't have any glass bottles on hand. Store in the refrigerator for up to 2 weeks.