Preheat oven to 350 degrees
Line a 2 1/4" muffin tin with cupcake wrappers
In a food processor, crush the wafer cookies
Mix the crushed cookies and the melted butter together
Divide the cookie mixture evenly between the cupcake wrappers
Using a shot glass, press the cookies into the bottom of the cupcake wrappers and set aside
In a large bowl, using either a hand mixer or a stand mixer, beat together the sugar and cream cheese until smooth
Beat in the eggs, vanilla, and corn starch until blended
Stir in the sour cream
Pour the mixture on top of each cookie crust
Bake for 15 minutes
Remove from oven and allow mini cheesecakes to cool, then remove the cupcake wrappers
While the cheesecakes are cooling, use a hand mixer or stand mixer and mix together all of the frosting ingredients until smooth
Add the frosting to a piping bag or a resealable plastic bag and snip off the corner
Pipe the frosting on to the cheesecakes
Using a small metal strainer, dust the cheesecakes with cocoa powder
Top each cheesecake with an espresso bean