In a bowl, pour espresso, Kahlua, and vodka and mix.
In a separate bowl, add gelatin and water and mix vigorously. Let the gelatin rest for 1 minute to bloom.
Microwave the gelatin mixture for 30-second intervals, 1 minute total. Do not microwave for 1 minute straight.
Add the hot gelatin to the espresso mixture and mix well.
Pour the mixture into the mini martini cups, about ¾ of the way up, leaving room for the foam.
Refrigerate for 3 hours.
Add the leftover espresso mixture to a bowl and use a frother to get the espresso "foam". Whip it up for 1 minute or so until you see it foam up.
Add the foam to the top of the espresso jello shot and let set up for another hour.
Add espresso beans to garnish (optional).
