Freeze the bowl and whisk (or beaters) for 20 minutes prior to making the ice cream.
Whip the heavy cream on high speed until stiff peaks form. This will take approximately 3-4 minutes.
Fold the sweetened milk, espresso powder, Irish whiskey, vanilla extract, and Creme de Menthe into the whipped cream.
Whip the ice cream mixture for an additional 1 minute, and then spoon into a 9 x 5 loaf pan, or into a freezable container.
Cover with plastic wrap and freeze for at least 4 hours or overnight.
Before serving, allow the ice cream to sit at room temperature for 5-7 minutes before scooping.
For the 21 and older crowd, only!