How to Make It
In a 1/2-gallon mason jar or pitcher, combine the kiwi and sugar. Cover and refrigerate for 48 hours.
In a medium saucepan, gently simmer the milk over low heat until it develops a thin film and tiny bubbles appear around the edge of the pan, about 10 minutes. Do not let the milk boil.
Add the gin and sherry to the kiwi mixture and stir until the sugar is completely dissolved. Pour the warm milk into the kiwi mixture (it will curdle) and let stand for 30 minutes.
Strain half of the punch mixture into another jar or pitcher through cheesecloth. Strain the remaining punch through fresh cheesecloth. Cover and refrigerate overnight to allow the remaining curds to settle.
Carefully ladle the clear punch into a bottle, without disturbing the solids at the bottom, and refrigerate; discard the curds. The clarified punch can be refrigerated for up to 2 weeks.
To serve, pour the punch into chilled rocks glasses over a large ice cube or smaller cubes. Garnish each drink with 1 or 2 drops of coffee extract.