From Martha Stewart Living
1 Cup Fresh Mint Leaves (washed and stems discarded)
1/2 Cup Sugar
1 Cup Milk
1 Cup Heavy Cream
Combine the mint and sugar in a bowl. Using the back of a wooden spoon, press the sugar into the mint leaves (mortar and pestle style) until the sugar resembles wet sand. Stir in milk and heavy cream; refrigerate at least 2 hours ( I like to do it overnight). Strain the mixture, and discard the mint solids. Freeze mixture in an ice-cream maker according to manufacturer's instructions.
* if you would like it to have a stronger mint flavor you can add a few drops of food-grade peppermint oil to the mixture before adding to the ice-cream maker.